The radius of a circle is 18 in. Find its area in terms of piπ.
The formula for the area of a circle is A = πr^2, where r is the radius of the circle.
Given that the radius is 18 in, we can plug this value into the formula:
A = π(18)^2
A = π(324)
A = 324π
Therefore, the area of the circle is 324π square inches.