Question

What is the surface area of a cylindrical ring if its outside diameter is 16 mm and its inside diameter is 10 mm? Round your answer to the nearest whole number
A. 92 mm2
B. 385 mm2
C. 118 mm2
D. 123 mm2

Answer 1

123 mm2
Given is diameter convert to radius
Then it is simple
Answer = pi (r1 square - r2 square)

Answer 2

Answer:

123 sq.mm.

Step-by-step explanation:

Outside diameter = 16 mm

Outer Radius = 16/2 = 8 mm

Inner diameter = 10 mm

Inner radius = 10/2 = 5 mm

Area of ring = Outer surface area - inner surface area

                     = π R^2 - π r^2

                     = 3.14(8^2-5^2)

                     = 122.571428571

Thus the surface area of ring is 123 sq.mm.