Given the diameter, the area of a circle is

area = (Pi/4)d

For your circle, the area is

area = (Pi/4)(10 ft)

area = (Pi/4)d

^{2}For your circle, the area is

area = (Pi/4)(10 ft)

^{2}= 25*Pi ft^{2}≈ 78.54 ft^{2}