The area of a rectangle, one side of which is 13 cm, is equal to 78 cm squared, find the perimeter of this rectangle?

Find what is the length of the second side of this rectangle.

We denote this length by x.

According to the condition of the problem, the length of one side of this rectangle is 13 cm, and its area is 78 cm², therefore, we can draw up the following equation:

x * 13 = 78.

Solving this equation, we get:

x = 78/13;

x = 6 cm.

Knowing the lengths of two adjacent sides of a given rectangle, we can calculate the perimeter P of this rectangle:

P = 2 * (13 + 6) = 2 * 19 = 38 cm.

Answer: the perimeter of this rectangle is 38 cm.