we know that
perimeter of the figure=perimeter of semi circle+perimeter of rectangle
so
perimeter of semicircle=2*pi*r/2----> pi*r
diameter=6 yd
radius r=6/2----> r=3 yd
convert to ft
1 yd ------> is equal to 3 ft
3 yd-----> x
x=3*3----> x=9 ft
so
diameter=18 ft
radius=9 ft
perimeter of semicircle=pi*9----> 28.26 ft
perimeter of rectangle=18+15+15----> 48 ft
perimeter of the figure=28.26 ft+48 ft-----> 76.26 ft
the answer is
76.26 ft