An isosceles triangle is given, the perimeter of which is 18 cm.

An isosceles triangle is given, the perimeter of which is 18 cm. Calculate the sides of the triangle if its base is 3 cm longer than the length of the side side.

1. Vertices of the triangle A, B, C. AB = BC.

2. We take as x (centimeters) the length of each of the lateral sides (AB and BC). Then the length of the base of the AC (x + 3) centimeters.

3. Let’s make an equation, taking into account that the total length of the sides and base of a given triangle is 18 centimeters:

x + x + (x + 3) = 18;

3x = 15;

x = 5 centimeters.

Base length 5 + 3 = 8 centimeters.

Answer: the length of each of the lateral sides (AB and BC) of the triangle ABC is 5 centimeters, the length of the base of the AC is 8 centimeters.