Angela goes to the garden. There is a fountain. A circular fountain with a 10m radius lies alone in the center of a circular park with a 200 m radius. Calculate the total walking area available to the park visitors.

First find the area of the garden then subtract the area of the fountain. This will leave the walking area.

Fountain

A = pi * 10^2

A = 100pi

Garden

A = pi * 200^2

A = 40,000pi

40,000pi - 100pi = 39,900 m^2

Area of circle = pi * radius^2

Walking area = Area of garden - area occupied by fountain

Area of garden = 3.14 ... * 200^2

= 40000pi

Area occupied by fountain = 3.14 ... * 10^2

= 100pi

Walking area = 40000pi - 100pi = 39900pi

= 125349.5469 m^2