Question

The height of a cone is two times its base diameter. What is the volume of the cone in terms of its base radius r? V = r2 V = r3 V = r3 V = r2

Answer 1

so hmm check the picture below

the radius "r" is half the diameter, meaning, the diameter is 2r long
now, if the height "h" is twice "d" or 2d, then that means h = 2(2r)

thus    $\bf \textit{volume of a cone}\\\\ V=\cfrac{\pi r^2 h}{3}\qquad \begin{cases} h=height\\ r=radius\\ ------\\ h=2(2r) \end{cases}\implies V=\cfrac{\pi r^2[2(2r)]}{3} \\\\\\ V=\cfrac{4\pi r^3}{3}$