1

A cone has a base diameter of $8$ cm and a vertical height of $8$ cm. Work out the volume of the cone.

2

A solid cone has base radius $9$ cm and vertical height $12$ cm. Work out the total surface area of the cone. Give your answer correct to 3 significant figures. (Curved surface area of a cone $= \pi r l$, where $l$ is the slant height.)

3

Two cones are joined base-to-base to make a solid. Both cones have base radius $r$ cm. One cone has slant height $4r$ cm and the other has slant height $5r$ cm. The total curved surface area of the solid is $300\pi$ cm². Work out the value of $r$. Give your answer correct to 3 significant figures. (Curved surface area of a cone $= \pi r l$.)