A circle is cut out of a piece of plywood that is 10 inches square The scraps are then thrown away How many square inches of plywood are thrown away?
The area of the square was 100 sq in (10 x 10). Assuming the circle was cut out of the square form edge to edge, the area of the 10 inch diameter circle is found as follows: A = Pi x R² where Pi is 3.1416 and R² is the radius multiplied by itself (the radius is one half of the diameter). Using the formula: A = 3.1416 x (5 x 5) = 3.1416 x 25 = 78.54 sq in. Subtract the area of the circle from the area of the square to find how much material was thrown away. (100 - 78.54 = 21.46 sq in)