A solid toy is in the form of a hemisphere surmounted by a right circular come. Height of the cone is 2 cm and the diameter of the base is 4 cm. /if a right circular cylinder circumscribes the toy, find how much more space it will cover.
Given radius of cone, cylinder & hemisphere (r) = 4/2 = 2 cm
Height of cone (l) = 2 cm
Height of cylinder (h) = 4 cm
Volume of cylinder = 
h = 
(4) cm …….. (1)
Volume of cone = 
= 
= 
× 4 × 2 cm ………………. (2)
Volume of hemisphere = 
= 
= 
…………….. (3)
So remaining volume of cylinder when toy is instead to it
= eq.(1) – eq.(2) + eq.(3)
= π(2)2(4) – (
× π × 8)
= 16π - 
π (4+8)
= 16π – 8π
= 8π cm3
∴ So remaining volume of cylinder when toy is instead to it = 8π cm3
22