Final answer:
To find out the number of pieces in the puzzle, divide the total area of the puzzle by the area of each piece.
Step-by-step explanation:
To find out how many pieces are in the puzzle, we need to know the area of each piece and the total area of the puzzle. The area of a circle is found using the formula A = πr^2, where r is the radius. In this case, the diameter of the puzzle is 20 inches, so the radius is half of that, which is 10 inches. Plugging this value into the formula, we get A = π(10)^2 = 100π square inches. The total area of the puzzle is equal to the sum of the areas of all the individual pieces, so we can divide the total area of the puzzle by the area of each piece to find out approximately how many pieces there are. However, without knowing the area of each piece, we cannot calculate the exact number of pieces.