The perimeter of the rectangle is 410 cm. The length of one side is 128 cm. Find the lengths of the other three sides.

In order to find the three unknown sides of a rectangle, we will compose an equation and solve it using the formula for finding the perimeter of a rectangle.

From the condition it is known that the perimeter of the rectangle is 410 cm.The length of one of the sides is also known – 128 cm.

In a rectangle, opposite sides are equal.

Let’s recall the formula by which they are looking for the perimeter of a rectangle:

P = 2 (a + b);

Let x cm be the length of the unknown side.

2 (x + 128) = 410;

x + 128 = 410: 2;

x + 128 = 205;

x = 205 – 128;

x = 77 cm.

Answer: 77 cm; 128 cm; 77 cm.