Question

A cylinder has radius 2.5 cm and lateral area 20 pi cm^2. What is the surface area of the cylinder in terms of pi?

Answer 1

This is the concept of areas of solid materials; the surface area of the cylinder whose radius is 2.5 cm and lateral area is 20 pi cm^2 will be: Surface area of cylinder is given by:
SA=(area of cyclic sides)+(lateral area)
SA=2πr^2+πrl
Area of the cyclic sides will be:
Area=2πr^2
=2*π*2.5^2
=12.5π cm^2
The lateral area is given by:
Area=20π cm^2
Therefore the surface area of cylinder will be:
SA=(12.5π+20π) cm^2
SA=32.5π cm^2
The answer is 32.5π cm^2