First, find the perimeter of the rectangle. 12+12+3+3=30ft. Next, find the perimeter of the semicircles. You can tell that if you put the semicircles together it would be a full circle. The formula for the perimeter of a circle is r2pi. The radius times 2 would be 6. Pi is approximately 3.14. 6 times 3.14 is 18.84. 18.84+30=48.84ft. Hope this helped :)