The perimeter of the rectangle is 54cm, and its length is 3cm longer than its width. Find the sides of the rectangle by equation.

1. Let the width be c and the length 3 + c. Let’s compose an equation based on the perimeter formula P = 2a + 2b, where P is the perimeter of a rectangle with length a and width b:
54 = 2s + 2 * (3 + s),
2s + 6 + 2s = 54,
4s = 54 – 6,
4s = 48,
c = 48/4,
c = 12.
2. find the length of the rectangle:
12 + 3 = 15 cm.
Answer: the width of the rectangle is 12 cm and the length is 15 cm.