Answer:
C.4.5 ft^2
Explanation:
If the area of the whole circle is 18 ft^2, and a whole circle is 360 degrees, and you are looking for the area of 90 degrees of that circle (which is one fourth of the circle) you would divide the area by 4, to get the area for that sector.
360/90= 4: meaning that 90 degrees is 1/4 of a circle.
So, you would divide 18 by 4.
18/4=4.5
Hope this helps!