Question

If the radius of the base of a cone is tripled and the height is doubled then the volume is

Options

• made 6 times

• made 18 times

• made 12 times

• unchanged

Answer 1

made 18 times

Explanation;

Hint:

Radius of a cone = r

Height of a cone = h

Volume of the cone = `1/3` πr²h cu.units

When the radius is increased three-time (tripled) and the height is doubled

Radius is 3r and the height is 2h

Volume of the new cone

= `1/3 pi(3pi)^2 xx 2"h"`

= `1/3 pi xx 9pi^2 xx 2"h"`

= `1/3 pi"r"^2"h"  (18)`

Volume is increased 18 times.