College

The volume of a cone with a radius of 7 cm is [tex]147 \pi[/tex] cubic centimeters. Which expression can be used to find [tex]h[/tex], the height of the cone?

A. [tex]147 \pi = \frac{1}{3}(7)(h)[/tex]

B. [tex]147 \pi = \frac{1}{3} \pi \left(7^2\right)(h)[/tex]

C. [tex]147 \pi = \frac{1}{3} \pi h[/tex]

D. [tex]147 \pi = \frac{1}{3} \pi(7)(h)[/tex]

Answer :

To find the height [tex]\( h \)[/tex] of the cone, we need to use the formula for the volume of a cone. The formula for the volume [tex]\( V \)[/tex] of a cone is given by:

[tex]\[ V = \frac{1}{3} \pi r^2 h \][/tex]

In this problem, the given volume of the cone is [tex]\( 147 \pi \)[/tex] cubic centimeters, and the radius [tex]\( r \)[/tex] is 7 cm. We'll plug these values into the volume formula and solve for [tex]\( h \)[/tex].

1. Substitute the known values into the volume formula:

[tex]\[ 147 \pi = \frac{1}{3} \pi (7)^2 h \][/tex]

2. Simplify the expression by calculating [tex]\( 7^2 \)[/tex]:

[tex]\[ 7^2 = 49 \][/tex]

Now the equation becomes:

[tex]\[ 147 \pi = \frac{1}{3} \pi \times 49 \times h \][/tex]

3. To solve for [tex]\( h \)[/tex], first eliminate [tex]\( \pi \)[/tex] from both sides of the equation:

[tex]\[ 147 = \frac{1}{3} \times 49 \times h \][/tex]

4. Multiply both sides by 3 to get rid of the fraction:

[tex]\[ 147 \times 3 = 49 \times h \][/tex]

5. Calculate [tex]\( 147 \times 3 \)[/tex]:

[tex]\[ 147 \times 3 = 441 \][/tex]

So, the equation is now:

[tex]\[ 441 = 49 \times h \][/tex]

6. Finally, solve for [tex]\( h \)[/tex] by dividing both sides by 49:

[tex]\[ h = \frac{441}{49} \][/tex]

7. Calculate [tex]\( \frac{441}{49} \)[/tex] to find the height [tex]\( h \)[/tex]:

[tex]\[ h = 9 \][/tex]

So, the height of the cone is 9 cm. Therefore, the expression that can be used to find [tex]\( h \)[/tex] is:

[tex]\[ 147 \pi = \frac{1}{3} \pi (7^2) h \][/tex]

And using this expression, the height [tex]\( h \)[/tex] is 9 cm.