Surface area and volume — practice question

The diagrams depict a solid cone together with a solid hemisphere. The cone has radius 2.4 cm and slant height 6.3 cm. The hemisphere has radius $R$ cm. The cone's total surface area is the same as the hemisphere's total surface area. For a cone with radius $r$ and slant height $l$, the curved surface area, $A$, is $A = \pi r l$. For a sphere with radius $r$, the curved surface area, $A$, is $A = 4\pi r^2$. (b) The diagram shows a solid cone with radius 7.6 cm and height 16 cm. A cut is made parallel to the base of the cone and the top section is removed. The remaining solid has height 12 cm. For a cone with radius $r$ and height $h$, the volume, $V$, is $V = \frac{1}{3}\pi r^2 h$.