The complete question in the attached figure
we know that
[area of a circle]=pi*r²
[length of the circumference]=2*pi*r
Part A)
(2 half circles=1 whoole circle)
radius r=20/2----> r=10 ft
[area 2 half circles]=pi*r²----> pi*10²----> 314.16 ft²
[perimeter 2 half circles]=2*pi*r-----> 2*pi*10----> 62.83 ft
Part B) 1/4 big circle
diameter=40 ft
radius=20 ft
[area 1/4 big circle]=pi*r²/4-----> pi*20²/4---> 314.16 ft²
[perimeter of 1/4 big circle]=2*pi*r/4-----> pi*20/2----> 31.42 ft
[area of the fountain]=314.16+314.16-----> 628.32 ft²------> 628 ft²
[perimeter <span>
of the fountain]=62.83+31.42-----> 94.25 ft</span>
-------> 94.3 ft