The shaded part represents the remaining cardboard. What is the area of the remaining cardboard?

Question

Madelyn had a square piece of cardboard that was 10 inches in length. She cut one 3-inch square from each corner, as shown below.

Answer 1

I am assuming that each corner of the 10 inch square cardboard had a 3 inch square cut off.

To find the area after removing the four 3 inch squares, we can determine the area of the 10 inch square and then subtract the area of four 3 inches squares. That would give us the area of the leftover cardboard.

Area of 10 inch square: 10 x 10 = 100 square inches

Area of one 3 inch square: 3 * 3 = 9 square inches

Area of four 3 inches squares: 4 * 9 = 36 square inches

Final area after removing the four 3 inch squares: 100 - 36 = 64 square inches