Question

What is the surface area of a cylindrical ring if its outside diameter is 16mm and its inside diameter is 10mm? Round your answer to the nearest hole number.

A-123mm^2
B-118mm^2
C- 92mm^2
D- 385mm^2

Answer 1

If it is a 2D disc then there is a correct option. The area would be:

Area of outer circle - area of inner circle.
Area of circle = π*r^2, so:

π * (16/2)^2 - π * (10/2) = 122.5

So A) 123mm^2.