What is the area of a 12 inch and a 9 inch circle?

Answer 1

The area of a circle is calculated using the formula A = πr^2, where r is the radius of the circle. For a 12-inch circle, the radius is half of the diameter, so the radius is 6 inches. Therefore, the area of the 12-inch circle is A = π(6)^2 = 36π square inches. Similarly, for a 9-inch circle, the radius is 4.5 inches, so the area of the 9-inch circle is A = π(4.5)^2 = 20.25π square inches.

Answer 2

If you are talking about 9 and 12 inch diameter, then divide both by 2 to get the radius. The area of a circle is pi (3.1415 is good for most calculations) multiplied by the square of the radius. So for the 12 inch circle, the radius is 6. The square of the radius is 36, and multiplying this by pi gives approximately 113.1 square inches.

Now the 9 inch circle has a radius of 9/2 or 4.5. Squaring this we get 20.25, which multiplied by pi is approximately 63.6 square inches.

If 9 and 12 were already the radius in the problem, just don't divide by 2 since you already have the radius.