The area of the rectangle is 72 cm2, one of its sides is 80 mm long, find the 2 side.

First, we translate millimeters into centimeters, based on the fact that 1 cm = 10 mm.
80/10 = 8 cm.
It is known that the area of a rectangle is calculated by the formula, the width of the rectangle is multiplied by the length of the rectangle: S = a * b.
Substituting the known values of the area and the first side of the rectangle in the formula, we get the following equation: 72 = 8 * b.
Let us find from the obtained equation the length of the rectangle: b = 72/8 = 9 cm.
Answer: The length of the rectangle is 9 cm.