The lengths of the sides of a triangle are 7: 5: 3. Calculate the sides of a triangle if its perimeter is 75 cm.

1. Since the lengths of the sides of the triangle are 7: 5: 3, we will designate them as “7X”, “5X” and “3X”.

The perimeter of a triangle is equal to the sum of the lengths of its sides. Let’s compose and solve the equation if the perimeter of the triangle is 75 cm:

7X + 5X + 3X = 75;

15X = 75;

X = 75/15;

X = 5.

2. Find the sides of the triangle:

7 * 5 = 35 (cm);

5 * 5 = 25 (cm);

3 * 5 = 15 (cm).

Answer: the sides of the triangle are 35 cm, 25 cm and 15 cm.