Find the third side of the triangle if its two sides are 21 cm and 32 cm, respectively

Find the third side of the triangle if its two sides are 21 cm and 32 cm, respectively, and the perimeter of the triangle is 100 cm.

The perimeter of a triangle is the sum of the lengths of all its sides.

Let’s call the triangle ABC, then we find the perimeter by the formula:

PABC = AB + BC + AC.

Side AB = 21 cm.

BC side = 32 cm.

Find AC -?

AC = PABC – AB – BC = PABC – (AB + BC).

Plug in the known values and calculate the unknown side.

AC = 100 – (21 + 32) = 100 – 53 = 47 cm.

Answer: the third side of the triangle is 47 cm.