What is the area of circle with diameter of 40m in terms of n?

The area of a circle is calculated using the formula ( A = \pi r^2 ), where ( r ) is the radius. Given a diameter of 40 meters, the radius is ( r = \frac{40}{2} = 20 ) meters. Therefore, the area is ( A = \pi (20)^2 = 400\pi ) square meters. In terms of ( n ), it can be expressed as ( A = 400n ) if ( n = \pi ).