Since we know the Circumference of the inner circle, we can divide by (pi symbol) to get the diameter of the inner circle.
87.92/3.14=28
With knowledge of 28 being the diameter, we can also solve for the radius, which is 14.
The area of the inner circle is (pi)14^2
The inner circle’s are is 615.44 unit^2
The outer circle’s radius is 14+7 or 21
(pi)21^2= 1,384.74
We subtract the inner circle’s area from the outer circle’s area.
1,384.74-615.44= 769.3
769.3 square kilometers
