Question

Two similar cylinders have radii of 15 inches and 6 inches. What is the ratio of the surface area of the small cylinder to the surface area of the large cylinder.

Answer 1

4:25

Explanation:

Given that,

r₁ = 15 inches, r₂ = 6 inches

The area of the cylinder is given by :

`A=2\pi rh+2\pi r^2`

The ratio of surface areas of two cylinders,

`(S_2)/(S_1)=(2\pi r_2h_2+2\pi r_2^2)/(2\pi r_1h_1+2\pi r_1^2)\\\\(S_2)/(S_1)=((r_2)/(r_1))^2\\\\=(6)/(15)^2\\\\=(4)/(25)`

Hence, the required ratio is 4:25.