Hi there!
![\large\boxed{r = 5 cm}](https://img.qammunity.org/2022/formulas/mathematics/high-school/y0uqwlcbwhewtj21hi2vbcdb374cazzppj.png)
The volume of a cone is as follows:
V = 1/3πr²h
We are given the volume and height, thus:
100π = 1/3πr²(12)
Begin by multiplying both sides by 3 (to cancel out the fraction):
300π = πr²(12)
Divide both sides by 12:
25π = πr²
Divide both sides by π:
25 = r²
Square root both sides:
5 = r