Question

At a zoo, the lion pen has a ring-shaped sidewalk around it. The outer edge of the sidewalk is a circle with a radius of 11 m. The inner edge of the sidewalk is a circle with a radius of 9 m.
⦁ Write and simplify an expression for the exact area of the sidewalk.

⦁ Find the approximate area of the sidewalk. Use 3.14 to approximate π

Answer 1

Outer radius: Ro = 11 m
Inner radius: Ri = 9 m

Area of the sidewalk: A = π (Ro^2 - Ri^2)
A = π ( (11 m)^2 - (9 m)^2 )
A= π ( 121 m^2 - 81 m^2 )
A = π ( 40 m^2 )
A= 40π m^2

The exact area of the sidewalk is 40π square meters

A = 40 (3.14) m^2
A = 125.6 m^2

The approcimate area of the sidewalk is 125.6 m^2