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.

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

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