Derive the formula V = (2/3)R 3 for the volume of a hemisphere of radius R by comparing its cross-sections with the cross-sections of a

Derive the formula V = (2/3)πR³ for the volume of a hemisphere of radius R by comparing its cross-sections with the cross-sections of a solid right circular cylinder of radius R and height R from which a solid right circular cone of base radius R and height R has been removed, as suggested by the accompanying figure.

VR - h R R h