A triangle has two sides of the same length. The perimeter of the triangle is 16 cm and the third side is 4 cm.

A triangle has two sides of the same length. The perimeter of the triangle is 16 cm and the third side is 4 cm. What are the lengths of the first and second sides of the triangle?

Perimeter is the sum of the lengths of all sides of a geometric figure.
The perimeter of a triangle is found by the formula:
P = a + b + c, where a, b, c are the sides of the triangle.
The problem says that 2 sides are equal, that is, a = b, and one side is 4 centimeters (c = 4 cm):
16 = a + b + 4;
a + b = 16 – 4;
a + b = 12 cm;
a = b;
12: 2 = 6 cm.
Answer: 6 centimeters is the length of the first and second sides of the triangle.