since its 2 half circles calculate are for a circle would be area = piR^2
the diameter is 100 feet so radius would be 100/2 = 50 feet
using 3.14 for pi you get 50^2 x 3.14 = 7850 square feet for the circle area
rectangle area = l x w = 100 x 212 = 21200
now add them
21200 + 7850 = 29050 square feet