A metronome is a device that ticks at adjustable intervals to help keep time when playing music. the metronome on ryan’s piano has the basic shape below. a square pyramid. the base is 9 centimeters by 9 centimeters. the triangular sides have a base of 9 centimeters and height of 20.5 centimeters. the pyramid has a height of 20 centimeters. if the metronome was created out of a piece of solid wood, what is the minimum amount of solid wood that was used? 369 centimeters cubed 450 centimeters cubed 540 centimeters cubed 810 centimeters cubed

Answers

Answer 1

When the metronome was created out of a piece of solid wood, the minimum amount of solid wood that was used from the pyramid will be C. 540 centimeters cubed.

How to calculate the pyramid?

From the information given, the metronome ticks at adjustable intervals to help keep time when playing music.

In rhis case, when the metronome was created out of a piece of solid wood, the minimum amount of solid wood that was used from the pyramid will be:

= 20 × 9 × ✓9

= 20 × 9 × 3

= 540

Learn more about pyramid on:

https://brainly.com/question/218706

#SPJ4

Answer 2

Answer:

540

Step-by-step explanation:

C


Related Questions


Use the given values to complete the table for the function below
y=2x^2+8x-5

Answers

What your gonna want to do is any where there is an x you are going to put in the number from the x column. You then solve for y and that is the answer for that number you used for x that would be your y

The measure of angle CDE is
degrees.

Answers

CDE = CDB + BDA + ADE

CDE = 42° + 37° + 20°

CDE = 99°

hope it helps...!!!

Answer:99 degrees

Step-by-step explanation:

Angle CDB + Angle BDA + Angle ADE= Angle CDE

42+37+20=99

Active
3
2
D(X)
4 5
de
8
9
TIME REMAINING
50:16
10
Which input value produces the same output value for
the two functions on the graph?
O x=-1
O
x = 0
O
x = 3
O x = 4
what’s the answer

Answers

i believe that the answer should be x = 4.

Answer:If your in FLVS i don't really know because this give really hard things. Wish you luck

Step-by-step explanation:

What is Parabola?

What is the transformation of parabolas?

Answers

Answer:

What is Parabola:

a symmetrical open plane curve formed by the intersection of a cone with a plane parallel to its side. The path of a projectile under the influence of gravity ideally follows a curve of this shape.

What is the transformation of parabolas?

The function y=x2+b has a graph which simply looks like the standard parabola with the vertex shifted b units along the y-axis. Thus the vertex is located at (0,b). If b is positive, then the parabola moves upwards and, if b is negative, it moves downwards. Similarly, we can translate the parabola horizontally

Step-by-step explanation:

Point D is the midpoint of AB and point E is the midpoint of BC. Select all of the statements to the right that must be true.

Answers

Answer + Step-by-step explanation:

» ABC ≅ DBE

» DE // AC  

(properties of the mid-segment of a triangle)

» Length of DE = 1/2 length of AC  

(properties of the mid-segment of a triangle)

» ∠BDE = ∠DAC

(Corresponding angles)

i forgot how to do some maths so i need help: solve 2x + 3 = -1

Answers

2x + 3 = -1
-3 = -3

2x = -4
— —
2 2

x = -2

Hope this makes sense and helps :)

Hi student, let me help you out! :)

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

We are asked to solve the equation [tex]\pmb{2x+3=-1}[/tex].

[tex]\triangle~\fbox{\bf{KEY:}}[/tex]

The goal is to isolate x.

First, subtract 3 from both sides of the equal sign:

[tex]\mathrm{2x=-1-3}[/tex]

[tex]\mathrm{2x=-4}[/tex]

Now, divide both sides by 2:

[tex]\mathrm{x=-2}[/tex]

Hope it helps you out! :D

Ask in comments if any queries arise.

#StudyWithBrainly

~Just a smiley person helping fellow students :)

What is the smallest number of marbles that could be divided up either into bags of $18$ marbles or into bags of $42$ marbles, with no marbles left over in each case

Answers

The number that could be divided up either into bags of 18 marbles or into bags of 42 marbles is 126.

How to find that number?

The number that could be divided up either into bags of 18 marbles or into bags of 42 marbles, with no marbles left over in each case, is the lowest common multiple between these two numbers.

By decomposing these numbers as a product of primes, we get:

18 = 2*3*3

42 = 2*3*7

Notice that the first two prime factors are the same, but the third one changes. To get the first common multiple, we need to multiply both numbers by the third factor (the different one) of the other.

We will get:

18*7 = 126

42*3 = 126

Then 126 is the smallest number that can be divided by 18 and 42.

If you want to learn more about lowest common multiple:

https://brainly.com/question/10749076

#SPJ2

2. Find the value of x and y rounded to the nearest tenth.
x
34
45°
30°
a.
x = 24.0, y = 46.4
c.
x = 48.1, y = 139.3
d. x = 48.1, y = 46.4
b. x = 24.0, y = 139.3

Answers

Using relations in a right triangle, it is found that the values of x and y are given by: x = 24, y = 46.4, given by option a.

What are the relations in a right triangle?

The relations in a right triangle are given as follows:

The sine of an angle is given by the length of the opposite side to the angle divided by the length of the hypotenuse.The cosine of an angle is given by the length of the adjacent side to the angle divided by the length of the hypotenuse.The tangent of an angle is given by the length of the opposite side to the angle divided by the length of the adjacent side to the angle.

First, we start with the vertical line h that divides y, that is opposite to an angle of 30º, with hypotenuse 34, hence:

sin(30º) = h/34

0.5 = h/34

h = 17.

Then, h is opposite to an angle of 45º, while the hypotenuse is x, hence:

[tex]\sin{45^\circ} = \frac{17}{x}[/tex]

[tex]x = \frac{17}{\sin{45^\circ}}[/tex]

x = 24.

y is divided into two segments.

The first is the adjacent to the angle of 30º, while the hypotenuse is 34.The second is adjacent to the angle of 45º, while the hypotenuse is 24.

Then:

[tex]\cos{30^\circ} = \frac{y_1}{34}[/tex]

[tex]y_1 = 34\cos{30^\circ} = 29.4[/tex]

[tex]\cos{45^\circ} = \frac{y_2}{24}[/tex]

[tex]y_2 = 24\cos{45^\circ} = 17[/tex]

Then, the value of y is given by:

[tex]y = y_1 + y_2 = 29.4 + 17 = 46.4[/tex].

More can be learned about relations in a right triangle at https://brainly.com/question/26396675

#SPJ1

which of the following is true for the relation f(x)-x^2+8

Answers

Answer: A

Step-By-Step Explanation: if n is greater than or equal to 2 is an add integer then the domain of: f(x)-x^2+8 is the solution to the inequality 2+8 greater than or equal to 0. which of the following statements is true?

Which of the following is the formula for the volume of a cube? a. s3 b. s2 c. π r2 d. π r3​

Answers

Answer:

Step-by-step explanation:

Which of the following is the formula for the volume of a cube?

a. s³

b. s²

c. π r²

d. π r³​

V = s³

For his phone service, Chris pays a monthly fee of $25, and he pays an additional $0.06 per minute of use. The least he has been charged in a month is $86.74.
What are the possible numbers of minutes he has used his phone in a month?
Use M for the number of minutes, and solve your inequality for M.

Answers

Answer:

1029 minutes or 17.15 hours

Step-by-step explanation:

25+0.06M=86.74

0.06M=61.74

M=61.74/0.06=1029

HELP THIS IS URGENT!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! :((((((((((((((((

Answers

Answer:

1)acute triangle

2) right angle

3) obtuse triangle

Step-by-step explanation:

please mark me as brainlest

Answer:

1. Acute 2. Obtuse 3.  Right

Step-by-step explanation:

Obtuse Triangle Definition

An obtuse triangle is one that has an angle greater than 90°. Because all the angles in a triangle add up to 180°, the other two angles have to be acute (less than 90°). It's impossible for a triangle to have more than one obtuse angle.

Acute Triangle Definition

An acute triangle is defined as a triangle in which all of the angles are less than 90°. In other words, all of the angles in an acute triangle are acute.

A Right Triangle has a right angle

Hope this helps.

can someone help me here

NONSENSE=REPORT​

Answers

[tex] \huge \qquad \sf \: Answer[/tex]

Here we go ~

1. A circle can be named by their Centre, so here in the diagram it's :

Circle A

2. Name 4 radii :

Radii are the line segments that joins the centre and boundary of circle.

They are :

FAGABACA

3. 2 Major arcs :

considering two points on a circle, and joining them forms a curve ( you can say part of circumference )

When we consider two points two arcs are formed and the arc with more length is known as Major Arc

That is :

Major arc ECFMajor arc BEC

4. A Semicircle :

Semicircle is special arc which is formed when two arcs formed by the points are equals to one another... it's also half the Perimeter of circle.

that is :

Arc CF is a Semicircle

5. 3 minor arcs :

The arc formed by two points having lesser length is known as minor arc.

that is :

Arc EFArc BGArc FG

6. 3 Central angles :

Central angles are angles formed by arcs on centre of the circle ~

that is :

Angle FABAngle BAC Angle GAB

7. A diameter :

Diameter is a chord that passes through centre of the circle.

CF

8. Congruent Angles :

In the given figure, there are two equal/congruent angles that are ~

Angle BAG and Angle GAF

9. Adjacent arcs :

The arcs that have one common end point are known as Adjacent arcs ~

that are :

Arc FG and Arc GB

Answer:

A circle is named by its center.  The center of the given circle is A, therefore:

Name of the circle:  A

The radius is any line segment from the center of the circle to the perimeter.

Name 4 radii:  [tex]\sf AC, \quad AB, \quad AG, \quad A\,F[/tex]

A major arc is an arc whose measure is greater than 180°.

When naming a major arc, the first point and last point are the endpoints, and we also need include the name of any point between those two endpoints.

2 major arcs:  [tex]\sf \widehat{CEG},\quad \widehat{BCF}[/tex]

A semi-circle is half a circle with an arc that measures 180°.

Its endpoints lie on the diameter of the circle.  We need three points to name a semicircle (the endpoints and a point between the endpoints).

A semi-circle:  CEF

A minor arc is an arc whose measure is less than 180°.

3 minor arcs:  [tex]\sf \widehat{FG}, \quad \widehat{GB}, \quad \widehat{BC}[/tex]

A central angle has its vertex at the center of the circle, and is formed by 2 radii.  When naming the central angle, the middle letter is the center of the circle.

3 central angles:  [tex]\sf \angle F\,AG, \quad \angle GAB, \quad \angle BAC[/tex]

The diameter is the widest part of the circle.  It is a straight line segment that passes through the center of the circle.

A diameter:  CF

Congruent angles are angles with the same measure.
On the diagram, the same angle measures are indicated by the addition of the same number of dashes on the angle sign.

Congruent angles:  [tex]\sf \angle F\,AG, \quad \angle GAB[/tex]

Adjacent arcs are arcs that have one point in common.

Adjacent arcs:  [tex]\sf \widehat{GB}[/tex] and [tex]\sf \widehat{BC}[/tex]  (they share point B)

Solve y = x + 8 for x.
Ox=y+8
Ox=y-8
Ox=-y + 8
Ox=-y-8

Answers

Answer:

x= -y+8

Step-by-step explanation:

hope it's helpful

expression equivlant (x+5)^2

Answers

Answer:

(x+5) (x+5)

Step-by-step explanation:

it's just (x+5)^2 twice

What is the inverse of the function f(x) =
1/9x+ 2?

Answers

Answer:

[tex]f^{-1}(x) = 9x -18.[/tex]

Step-by-step explanation:

[tex]y=f(x)=\dfrac 19 x +2\\\\\text{Replace x with y and then solve for y,}\\\\~~~~~~~x = \dfrac 19 y+2\\\\\implies 9x =y + 18~~~~~~~~~~~~~~~;[\text{Multiply both sides by 9}]\\ \\\implies y = 9x -18\\\\\implies f^{-1}(x) = 9x -18\\\\\text{Hence, the inverse of the given function is}~ f^{-1}(x) = 9x -18.[/tex]

Question 2(Multiple Choice Worth 2 points)
(04.03 MC)
4x-7
Given f(x) =
8x+8
what is the end behavior of the function?

Answers

The end behavior is that as x approaches positive infinity, f(x) approaches positive infinity and as x approaches negative infinity, f(x) approaches negative infinity

How to determine the end behavior?

The function is given as:

f(x) = 8x+8

The above function is a linear function.

A linear function is represented as:

f(x) = mx + b

This means that the slope of f(x) is 8 (a positive number)

For a linear function with a positive slope, the end behavior is that:

As x approaches positive infinity, f(x) approaches positive infinity and as x approaches negative infinity, f(x) approaches negative infinity

Read more about end behavior at:

https://brainly.com/question/1365136

#SPJ1

A box contains 50 batteries, of which 10 are dead and 5 are weak. Suppose you select batteries at random from the box and set them aside for recycling if they are dead or weak. If the first battery you select is dead and the second one is weak, what is the probability that the next battery you select will be weak?

Answers

Probability of selecting 1 dead, 1 weak, then 1 weak = (1/588).

Given: 50 total batteries, of which 10 are dead and 5 are weak. This is represented by: 10/50 (simplifies to 1/5) and 5/50 (simplifies to 1/10).
If the batteries are being set aside, it likely means no replacement. For every battery taken out of the box, the box holds one less battery.

Probability of selecting 1 dead, 1 weak, 1 weak is written as: (10/50)*(5/49)*(4/48) = 1/588.

-
If f(x) = 3x² − 4 and g(x) = 2x − 6, what is g(f(2))?

Answers

[tex]\\ \rm\Rrightarrow g(f(2))[/tex]

[tex]\\ \rm\Rrightarrow g(3(2)²-4)[/tex]

[tex]\\ \rm\Rrightarrow g(12-4)[/tex]

[tex]\\ \rm\Rrightarrow g(8)[/tex]

[tex]\\ \rm\Rrightarrow 2(8)-6[/tex]

[tex]\\ \rm\Rrightarrow 16-6[/tex]

[tex]\\ \rm\Rrightarrow 10[/tex]

Answer:

[tex]g[f(2)] = 10[/tex]

Step-by-step explanation:

Given functions:

[tex]\begin{cases}f(x)=3x^2-4\\g(x)=2x-6\end{cases}[/tex]

Find f(2) by substituting [tex]x = 2[/tex] into function f(x):

[tex]\begin{aligned}\implies f(2)& =3(2)^2-4\\& = 3(4)-4\\& = 12-4\\& = 8\end{aligned}[/tex]

Now substitute the found value of f(2) into function g(x):

[tex]\begin{aligned}g[f(2)] & = 2[f(2)]-6\\\implies g[f(2)] & =2(8)-6\\& = 16-6\\& = 10\end{aligned}[/tex]

when the positive integer x is divided by 5, the remainder is 3. what is the remainder when X +19 is divided by five

Answers

Answer:

_4

Step-by-step explanation:

x+19/5=3 cross multiply

x+19=3*5

x+19=15

x=15-19

x=-4

The remainder when (x + 19) is divided by 5 is 2.

If the positive integer x has a remainder of 3 when divided by 5, it can be represented as:

x = 5a + 3, where "a" is a non-negative integer.

Now, let's consider the expression (x + 19) and determine the remainder when it is divided by 5:

x + 19 = (5a + 3) + 19

       = 5a + 22

When we divide 5a + 22 by 5, we find:

(5a + 22) = 5(a + 4) + 2

Therefore, the remainder when (x + 19) is divided by 5 is 2.

Learn more about remainders here:

https://brainly.com/question/29019179?

#SPJ2

i need help on this may you help

Answers

Answer:

should be 63

Step-by-step explanation:

10. Complete the equation to make a true statement. Use the number
bank to fill in the statement.
-7-4
-4-2 1 2 3
Enter your answers in the boxes:
7
-
=
7
[
OA. 3,-4
B. 2,-2
O C. 1;-4
D. 2; 3
+
* 1 pc

Answers

The option (B) 2,-2 is correct because the number satisfy the provided expression.

What is an arithmetic operation?

It is defined as the operation in which we do the addition of numbers, subtraction, multiplication, and division. It has a basic four operators that is +, -, ×, and ÷.

We have a number bank shown in the picture.

The problem given:

7 - __ =  7 +  __

A. 3,-4

Checking for the above option:

7 - 3 = 7 - 4

4 = 3 (false)

B. 2,-2

Checking for the above option:

7 - 2 = 7 - 2

5 = 5 (true)

O C. 1;-4

Checking for the above option:

7 - 1 = 7 - 4

6 = 3 (false)

D. 2; 3

Checking for the above option:

7 - 2 = 7 + 3

5 = 10 (false)

Thus, the option (B) 2,-2 is correct because the number satisfy the provided expression.

Learn more about the arithmetic operation here:

brainly.com/question/20595275

#SPJ1

Find the indicated conditional probability
using the following two-way table:
Grade
Drive to school Take the bus
Walk
Sophomore
2
25
3
Junior
13
20
2
Senior
25
5
5
P(Take the bus | Junior) = [?]
Round to the nearest hundredth.

Answers

Using it's concept, it is found that the desired probability is given by:

P(Take the bus | Junior) = 0.5714 = 57.14%.

What is a probability?

A probability is given by the number of desired outcomes divided by the number of total outcomes.

In this problem, we have that out of the 13 + 20 + 2 = 35 Junior students, 20 take the bus, hence the probability is given by:

P(Take the bus | Junior) = 20/35 = 0.5714 = 57.14%.

More can be learned about probabilities at https://brainly.com/question/14398287

#SPJ1

Which could be the missing data item for the given set of data if the median of the complete data set is 50?

21 23 60 60 50 54 54 59 26 15 43 15 A. 18
B. 24
C. 45
D. 57

Answers

Answer:

It's A

Step-by-step explanation:

Thx to the guy in the comments above

Answer:

It's A

Step-by-step explanation:

It's right

Which equation represents an inverse variation?
O y = 2x
O y= f
0 y=
4
5
O y = -5x

Answers

Answer:

its y=2x so yaa thats ittt

A sequence has a second term of 1 and a common difference of -3.
The fifth term of the sequence is
10
-5
-11
-8

Answers

Answer:

-11

Step-by-step explanation:

I don't know how to type Numerical using a cellphone

I think -11 Not 100% sure

Find the value of x y and z​

Answers

Answer:

x = 115° , y = 65° , z = 115°

Step-by-step explanation:

x and 65° are a linear pair and sum to 180°

x + 65° = 180° ( subtract 65° from both sides )

x = 115°

y and 65° are vertically opposite angles and are congruent , then

y = 65°

x and z are vertically opposite angles and are congruent , then

z = x = 115°

CPA is parallel to BPD and so it is also equal to 65 degrees

And all you have to do to find CPB is 180-65=115 and CPB is Parallel to APD thus, its equal to 115 too!

CPA= 65 degrees

BPD=65 degrees

APD= 115 degrees

CPB=115 degrees

Hope i helped

TheOneAndOnlyLara~

proving trigonometric identities

2(cosx sinx-sinx cos2x)/sin2x =secx

Answers

This is not an identity.

[tex]\dfrac{2(\cos(x)\sin(x) - \sin(x)\cos(2x))}{\sin(2x)} \neq \sec(x)[/tex]

Check x = π/4, for which we have cos(π/4) = sin(π/4) = 1/√2. Together with sin(2•π/4) = sin(π/2) = 1 and cos(2•π/4) = cos(π/2) = 0, the left side becomes 1, while sec(π/4) = 1/cos(π/4) = √2.

Keeping the left side unchanged, the correct identity would be

[tex]\dfrac{2(\cos(x)\sin(x) - \sin(x)\cos(2x))}{\sin(2x)} = -2\cos(x) + 1 + \sec(x)[/tex]

To show this, recall

• sin(2x) = 2 sin(x) cos(x)

• cos(2x) = cos²(x) - sin²(x)

• cos²(x) + sin²(x) = 1

Then we have

[tex]\dfrac{2(\cos(x)\sin(x) - \sin(x)\cos(2x))}{\sin(2x)} = \dfrac{2\cos(x)\sin(x) - 2\sin(x)\cos(2x)}{\sin(2x)} \\\\ = \dfrac{\sin(2x) - 2\sin(x)\cos(2x)}{\sin(2x)} \\\\ = 1 - \dfrac{2\sin(x)\cos(2x)}{\sin(2x)} \\\\ = 1 - \dfrac{2\sin(x)(\cos^2(x) - \sin^2(x))}{2 \sin(x)\cos(x)} \\\\ = 1 - \dfrac{\cos^2(x) - \sin^2(x)}{\cos(x)} \\\\ = 1 - \cos(x) + \dfrac{\sin^2(x)}{\cos(x)} \\\\ = 1 - \cos(x) + \dfrac{1 - \cos^2(x)}{\cos(x)} \\\\ = 1 - \cos(x) + \sec(x) - \cos(x) \\\\ = -2\cos(x) + 1 + \sec(x)[/tex]

What are the factors pair of 32.

Answers

Answer:

1&32 2&16 4&8

Step-by-step explanation:

Factor Pair Pair Factorization

1 and 32       1 x 32 = 32

2 and 16         2 x 16 = 32

4 and 8      4 x 8 = 32

can i have help with this

Answers

Answer:

2^1

Step-by-step explanation:

a^m/a^n = a^(m-n)

so, 2^8/2^7 = 2^(8-7) = 2^1

hope this helps :)

given expression , [tex]2^{8}/2^{7}[/tex]

If we observe closely ,

It is in the form of [tex]a^{m}/a^{n}[/tex]

Which is equal to [tex] a^{m-n}[/tex]

Now from given , we get it is [tex]2^{8-7}[/tex] = [tex] 2^{1}[/tex]

Option a is correct
Other Questions
Adjusting entries for accrued expenses ensure that liabilities are reported for all amounts ______ at the end of the accounting period. Reading fluently means students read text quickly and without having to stop to understand inflection or use context clues. Question 7 of 10Which product is undefined?A. CD, where C is a 3 x 1 matrix and D is a 1 x 2 matrixB. NP, where N is a 2 x 1 matrix and Pis a 1 x 4 matrixC. AB, where A is a 3 x 2 matrix and Bis a 3 x 1 matrixD. HK, where H is a 3 x 3 matrix and K is a 3 x 1 matrix Which data set contains an outlier: what is the volume of a cone with a diameter of 16 centimeters and a height of 15 centimeters? Every ecosystem has its own set of environmental stresses. What nonliving factors would cause stress to organisms in a forest ecosystem? What about a desert ecosystem? Which statement best expresses a shared theme about leadership in "How Theseus Lifted the Stone" and "How Arthur was chosen king"? Workers need to know the area of a park to determine how much grass seed to order. A worker drew a sketch of the park to find its area. Which is the area of the park? A cross is performed between a bird that is homozygous for red feathers and a bird that is homozygous for blue feathers. purple offspring result due to incomplete dominance. then, two of the purple offspring are crossed. what proportion of the offspring from the second cross will be purple? 1 in 4 2 in 4 3 in 4 4 in 4 What is one condition that is necessary for a hurricane to form Question 16 (5 points)Find the domain of the function y = 5/3 tan(/4^x).A) All real numbers except 0 and odd integer multiples of 4/3B) All real numbers except odd integer multiples of 2/3C) All real numbers except 0 and odd integer multiples of 2/3OD) All real numbers except odd integer multiples of 4/3 How were the policies of Hitler and Mussolini similar? all of these answers are correct both discontinued elections both used violence against dissenters both persecuted farm laborers Write the expression 5x(x + 9) 7(x + 9) in complete factored form.A. (x + 9)(x + 9)B. (5x 7)(x + 9)C. (5x 7)(x + 9)(x + 9)D. (5x2 + 45x)(-7x 63) An American architect whose principles of building included consonance with the landscape was ____________________________. the gas tank in minas car holds 15 gallons. Her car gets between 25 and 30 miles to the gallon. If Mina fills up the gas tank and then drives until she runs out of gas, what is the least number of miles she can drive?A. 300miB. 375miC. 405miD. 450mi evaluate 20(5 X 2/5 )+ 3 pls help what would you do or change if you were elected in congress? Forecast the 2019 Cost of goods sold on the previous years number and the assumptions. 2018 Actual 2019 Estimate Sales Growth 6% 8% Gross Margin 40% 40% Revenues 50,000 Cost of Goods Sold 30,000 Describe how you would The list below shows the ages of all the presidents inaugurated in the twentieth century. Make a stem-and-leaf plot to answer the question.42, 51, 56, 55, 51, 54, 51, 60, 62, 43, 55, 56, 61, 52, 69, 64, 46, 54In a stem-and-leaf plot of the data, how many leaves does stem 5 have?show the number 4 and 89 on a stem-and-leaf plot. How did the conservationist John Muir contribute to the protection and management of resources in the US?