# The perimeter of triangle ABC is 36 cm. The length of the side AB is 10 cm, the length

**The perimeter of triangle ABC is 36 cm. The length of the side AB is 10 cm, the length of the side BC is 4 cm longer. What is the length of the side of the speaker.**

1) Find the length of the BC side. If it is 4 cm longer than the AB side, then it is necessary to add 4 cm to the length of the AB side.

10 + 4 = 14 (cm).

2) Find the sum of the lengths of the sides AB and BC.

10 + 14 = 24 (cm).

3) Find the length of the AC side. We know the perimeter of the triangle ABC. The perimeter is the sum of the lengths of all the sides of the triangle. The sum of the two sides is known to us, 24 cm. To find the third side, it is necessary to subtract the sum of the lengths of the two sides from the perimeter of the triangle.

36 – 24 = 12 (cm).

Answer. The speaker side is 12 centimeters long.