Question

The height of a cone is equal to the diameter of the base.

Answer 1

we know that

the volume of a cone is equal to

$V=\frac{1}{3} \pi r^{2}h$

where

r is the radius of the base of the cone

h is the height of the cone

in this problem we have

$r=x\ units\\h=2x\ units$

substitute in the formula

$V=\frac{1}{3} \pi x^{2}2x$

$V=\frac{2}{3} \pi x^{3}\ units^{3}$

therefore

the answer is the option A

$\frac{2}{3} \pi x^{3}\ units^{3}$

Answer 2

A 2/3 pi x ^2 is the best choice