Question

the radii of 2 cylinder are in ratio 2:3 and heights in ratio 5:3. calculate ratio of their curved surface area

Answer 1

Let the two cylinders be A and B.

Radii of A = r

Radii of B = 3/2 r

Height of A = h

Height of B = 3/5h

Curved surface area = πdh

Curved surface area of A :

2rπh

Curved surface area of B :

π × 2 × 3/2r × 3/5h = 9/5πrh

The ratio of the curved surface area of A : B is :

2rπh / (9/5πrh) = 2πrh × 5/9πrh = 10/9

10 : 9