Final answer:
To find the area of the rectangle, calculate 40% of the length, 20 feet, to get the width, then multiply the length by this width. The area is 160 square feet.
Step-by-step explanation:
The question involves calculating the area of a rectangle.
Given that the width is 40% of the area and the length is 20 feet, we first need to determine the width in feet.
To calculate the area of the rectangle, we use the formula area = length × width.
Since the width is 40% of the length, we first need to find 40% of 20 feet, which is 0.40 × 20 = 8 feet.
Now that we have both the length and width, the area of the rectangle is 20 feet × 8 feet = 160 square feet.