The length of the rectangle is 3 times its width and the perimeter is 32 cm. Find the length and width of the rectangle.

The perimeter of a rectangle is equal to the sum of the lengths of its sides.
P = 2a + 2b
Let’s take the width of the rectangle as x.
Then the length of the rectangle is 3x.
P = 2x + 2 (3x) = 32
2x + 6x = 32
8x = 32
x = 32/8 = 4
The width of the rectangle is 4.
The length of the rectangle is 4×3 = 12.
Verification:
The perimeter of the rectangle is P = 4 + 4 + 12 + 12 = 32.