Final answer:
When a rectangle with an area of 40 square centimeters is cut in half, the area of each resulting piece is 20 square centimeters.
Step-by-step explanation:
The area of a rectangle is defined as the product of its length and width. Given that the area of the rectangle is 40 square centimeters, when you cut the rectangle in half, the area of each piece would also be halved. Therefore, each piece would have half the area of the original rectangle.
Area of each piece = Total area ÷ 2 = 40 cm² ÷ 2 = 20 square centimeters.
The correct answer is (b) 20 square centimeters.