How to find the lengths of the sides of a rectangle if the width of the rectangle is 30 mm less than the length

How to find the lengths of the sides of a rectangle if the width of the rectangle is 30 mm less than the length, and the perimeter is 14 cm.

1. Suppose the width of the given rectangle is x cm.
2. Since we know that its length is 30 mm longer, therefore it is equal to (x + 3) cm.
3. Knowing that the perimeter of a rectangle is the sum of the lengths of all its sides, we write down the equation and find out what its width is if we know that its perimeter is 14 cm.
x + x + (x + 3) + (x + 3) = 14;
x + x + x + 3 + x + 3 = 14;
4x = 14 – 3 – 3;
4x = 14 – 6;
4x = 8;
x = 8/4;
x = 2 cm.
4. Now we find out what the length is equal to.
2 + 3 = 5 cm.
Answer: The width of the rectangle is 2 cm, the length is 5 cm.