I think you have a semicircle on top of a right trapezoid.
The perimeter is πr+b1+b2+√(4r2+(b1-b2)2), where:
r=radius of the semicircle,
b1 and b2 are the lengths of the parallel bases (top and bottom sides) of the trapezoid.
It's assumed that the diameter of the semicircle forms the side of the trapezoid perpendicular to the bases.
(1) r=6yd and the trapezoid side is therefore 12yd not 12.04yd in length; or (2) r=6.02yd.
Assume (1) then the perimeter=6π+6+5+√(144+1)=41.89 yds approx.
Assume (2) then the perimeter=6.02π+6+5+√(144.96+1)=41.99 yds approx.