Use the correct formula to find the area of a circle if the diameter is 21 mi. Round to the nearest hundredths place. Use 3.14 for .
The formula to find the area of a circle is A = πr^2, where r is the radius.
Given that the diameter is 21 mi, we can find the radius by dividing the diameter by 2:
r = 21 mi / 2 = 10.5 mi
Now we can plug in the radius into the formula:
A = 3.14 * (10.5)^2
A = 3.14 * 110.25
A ≈ 345.68
Therefore, the area of the circle is approximately 345.68 square miles.