Given a triangle ABC with sides AB = 7 cm, BC = 11 cm, CA = 19 cm.

Given a triangle ABC with sides AB = 7 cm, BC = 11 cm, CA = 19 cm. Find the perimeter of the triangle DEF if it is known that each side is 2 cm less than that of the previous triangle.

The perimeter of triangle ABC is:

Pabc = AB + BC + AC.

Let’s find its value:

P = 7 + 11 + 19 = 37 cm.

Each side of triangle DEF is less than the sides of triangle ABC by 2 centimeters. This means that as a result, its perimeter will be less

3 * 2 = 6 cm.

Find the perimeter of the triangle DEF:

Pdef = 37 – 6 = 31 cm.

Answer: The perimeter of triangle DEF is 31 centimeters.