A circular print is being matted in a square frame. If the frame is 18 in by 18 in, and the radius of the print is 7 in, what is the area of the matting? (π = 3.14)
a. 477.86 in2
b. 170.14 in2
c. 280.04 in2
d. 288 in2
b. To evaluate the area of the matting, subtract the area of the print from the area of the frame. The area of the print is calculated using πr2 or (3.14)(7)2 which equals 153.86 in2. The area of the frame is length of side times length of side or (18)(18), which similar to 324 in2. The difference, 324 in2 - 153.86 in2 or 170.14 in2, is the area of the matting. If you select c, you mistakenly used the formula for the circumference of a circle, 2πr, instead of the area, πr2.