The perimeter of the triangle is 48 cm and one of the sides is 17 cm and the other 15 cm which is the third side.

For a given triangle, the lengths of its two sides (a = 17 m, b = 15 cm) and the perimeter (P = 48 cm) are known.

It is required to find the length of the third side (c =?).

To find its length, remember what the perimeter of a triangle is.

The perimeter of triangle 1 is the sum of the lengths of all its sides:

P = a + b + c.

From here, you can write the formula for finding the length of the third side:

c = P – (a + b).

Then

c = 48 – (17 + 15) = 48 – 32 = 16 cm.

Answer: 16 cm.