Answer:
~78.54 mi^2
Step-by-step explanation:
The area of a circle is defined as π r^2. The radius is 10 miles. 10^2 is 100. 100 x π is roughly 314.16. Since we know the angle is 90 degrees, we know that it makes up one fourth of the entire area. 314.16 divided by 4 is 78.54.
