# The perimeter of a triangle is 39 cm, and the length of one of its sides is 14 cm.

**The perimeter of a triangle is 39 cm, and the length of one of its sides is 14 cm. Find the lengths of the other two sides of the triangle if their difference is 2.4 cm.**

1) The perimeter of a triangle is equal to the sum of the lengths of all its sides. Knowing the size of the perimeter and one of its sides, you can find the total length of its other two sides:

39 – 14 = 25 cm.

2) Let one of the required sides of the triangle be x cm.

3) Then (x + 2.4) cm is the other desired side.

4) You can write:

x + (x + 2.4) = 25.

5) Solve the equation:

2x + 2.4 = 25;

2x = 25 – 2.4;

2x = 22.6;

x = 22.6: 2;

x = 11.3 cm.

6) This means that one of the required sides of the triangle is 11.3 cm.

7) Find the second required side:

11.3 + 2.4 = 13.7 cm.

Answer: 11.3 and 13.7 cm.