The lengths and widths of four rectangles are shown below. Which rectangle has a perimeter 20 of
ft?
A
length = 10 ft, width = 10 ft
B
length = 9 ft, width = 1ft
C
length = 7 ft, width = 2 ft
D
length = 5 ft, width = 2 ft
To find the perimeter of a rectangle, we use the formula P = 2(length + width).
For rectangle A, the perimeter is P = 2(10 + 10) = 2(20) = 40 ft.
For rectangle B, the perimeter is P = 2(9 + 1) = 2(10) = 20 ft.
For rectangle C, the perimeter is P = 2(7 + 2) = 2(9) = 18 ft.
For rectangle D, the perimeter is P = 2(5 + 2) = 2(7) = 14 ft.
Therefore, the rectangle with a perimeter of 20 ft is rectangle B.