The perimeter of a parallelogram is 42. Find all of its sides if one is 3 more than the other.

1. Let’s denote the smaller side of the parallelogram through x cm.

2. Determine the large side of the parallelogram:

(x + 3) cm.

3. Let’s compose and solve the equation:

(x + (x + 3)) * 2 = 42;

(x + x + 3) * 2 = 42;

(2x + 3) * 2 = 42;

4x + 6 = 42;

4x = 42 – 6;

4x = 36;

x = 36: 4;

x = 9.

4. The length of the shorter side of the parallelogram is x = 9 cm.

5. What is the longest side of the parallelogram?

x + 3 = 9 + 3 = 12 cm.

Answer: the sides of the rectangle are 9 cm, 12 cm, 9 cm, 12 cm.