The midline of an isosceles triangle is 3 cm. Find the side of the triangle if the perimeter is 16.

One of the properties of the midline of a triangle is that the length of this line is equal to half the length of the side to which this line is parallel. Since the middle line is parallel to the base of the triangle and is equal to 3 cm, the base of the triangle is:

3 * 2 = 6 cm.

Knowing that the triangle is isosceles, the base = 6 cm, and the perimeter (P) = 16, you can understand how long the side will be. On two equal sides of the triangle there are:

16 – 6 = 10 cm.

Since 10 cm is the length of two equal sides, the length of one side is:

10/2 = 5 cm.