To get perimeter you add all the sides together. You have 2 sides of 10ft, one side of 8ft and then the half circle. To find the arc length of the half circle you would do 1/2(2πr) which would give you πr. R=4ft since the diameter is 8ft. So you would add 8,10,10 and 4pi. If it wants an exact answer it would be 28+4pi. If it wants an approximate answer it would be 40.6ft
