The perimeter of the rectangle is 28 cm and one of the sides is 4 cm less than the other.Then the smaller side of the rectangle is …

In order to find the sides of a rectangle, you and I must compose and solve a linear equation.
Let’s start by introducing the variable x – denoting with it the length of one of the sides of the rectangle, then the length of the second side is (x – 4) cm.
It is also known from the condition that the perimeter of the rectangle is 28 cm.
We look for the perimeter of the rectangle by the formula:
P = 2 (a + b);
28 = 2 (x + (x – 4));
x + x – 4 = 28: 2;
2x – 4 = 14;
2x = 14 + 4;
2x = 18;
x = 18: 2;
x = 9 cm one side and 9 – 4 = 5 cm length of the second.