When 3 litres of oil is removed from an upright cylindrical can, the level falls by 10 cm. Find the radius of the can.

Hello!

Denote the radius of a can in cm as

Removed oil had the shape of a disk (upright circular cylinder). Its height is given, its volume is also given. The relation between them is

so

This is the answer.

Hello!

Denote the radius of a can in cm as

Removed oil had the shape of a disk (upright circular cylinder). Its height is given, its volume is also given. The relation between them is

so

This is the answer.