Assuming that the surface of the Frisbee is a flat circle, its area is 113 square inches,rounded to the nearest inch. One can reach that answer by using the formula for determining the area of a circle, which is pi times the square of the circle's radius.
The radius of a circle is always equal to half the diameter, so the radius of a 12-inch Frisbee is 6 inches. To find its square, multiply the radius by itself (6 x 6) to get 36. For pi, use the approximation 3.14. Multiply that by the square of the radius and get: 3.14 x 36 = 113.04, which, rounded to the nearest significant digit, comes out to 113 square inches.