So u need to find the circumference of the half circle by finding the circumference of the whole circle and dividing by 2 so that gives you 12.565 then u find the perimeter of the rectangle but not the 4th side cause that’s on the inside when u do that u get 10+10+8 which is 28 then add the half circle and I get 40.565 ft but round to nearest hundred so 40.56 ft