Question

find rhe volume of a cylinder with a diameter of 10 inches and a height of 20 inches

Answer 1

since the diameter of the cylinder is 10, its radius is half that, or 5, thus

$\bf \textit{volume of a cylinder}\\\\ V=\pi r^2 h~~ \begin{cases} r=radius\\ h=height\\ -----\\ r=5\\ h=20 \end{cases}\implies V=\pi (5)^2(20)$