Question

A and B are two cylinders that are mathematically similar.

The area of the cross-section of cylinder A is 18cm².
Height of A is 5cm.
Height of B is 10cm.

Work out the volume of cylinder B

Answer 1

720 cm³

Explanation:

Given 2 similar cylinders with

ratio of heights = a : b, then

ratio of areas = a² : b²

Here ratio of heights = 5 : 10 = 1 : 2, thus

ratio of areas = 1² : 2² = 1 : 4

cross section area of B is 4 times cross section area of A

cross section area of B = 4 × 18 = 72 cm²

volume of cylinder = cross section area × height

volume of cylinder B = 72 × 10 = 720 cm³