Find the perimeter of an isosceles triangle if the side is 16 cm and the apex angle is 60 degrees.

Let’s build an isosceles triangle with vertices A, B, C. AB = BC = 16 cm, the angle at the vertex B is 60 degrees.
To find the perimeter, you need to add all the sides of a given triangle. AB and BC are given to us, we need to find AC.
In any triangle, the sum of the angles is 180 degrees. We find the angles A and C. They, as well as the angle B, are equal to 60 degrees, hence the triangle ABC is equilateral. AB = BC = AC = 16 cm.
Substitute this value into the perimeter formula.
Answer: 48 cm