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)^2[/tex]

B. [tex]147 \pi = \frac{1}{3} \pi(7^2)(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 expression that can be used to determine the height [tex]\( h \)[/tex] of the cone, let's start by considering the formula for the volume of a cone, which is:

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

We are given:
- Volume [tex]\( V \)[/tex]: [tex]\( 147 \pi \)[/tex]
- Radius [tex]\( r \)[/tex]: 7 cm

Plug these values into the formula:

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

Now, we need to simplify this equation to solve for [tex]\( h \)[/tex].

1. Start by squaring the radius:

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

2. Substitute back into the equation:

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

3. The [tex]\(\pi\)[/tex] on both sides can be cancelled out:

[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. Simplify the left side:

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

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

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

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

Therefore, the expression that can be used to find [tex]\( h \)[/tex] is:

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

And from here, solving gives us a height [tex]\( h \)[/tex] of 9 cm. So, the correct expression from the options given corresponds to this process is:

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