The diameter of a circle is 18 in. Find its area in terms of piπ
To find the area of a circle, you can use the formula A = πr^2, where r is the radius of the circle. Since the diameter is given, we need to first find the radius.
The radius of a circle is half the length of the diameter, so the radius is 18 in / 2 = 9 in.
Now we can plug this radius value into the formula for the area:
A = π(9)^2
A = π(81)
A = 81π in^2
Therefore, the area of the circle is 81π square inches.