The lengths of the sides of the triangle are proportional to the numbers 4, 7, 9;

The lengths of the sides of the triangle are proportional to the numbers 4, 7, 9; the largest side exceeds the smallest by 10 cm. Find the perimeter of the triangle.

The fact that the sides of the triangle are proportional to the numbers 4, 7 and 9 means that there is such a number a, at which 4a, 7a and 9a are the numerical values of the lengths of the sides of this triangle in centimeters.

According to the condition of the problem, the largest side exceeds the smallest side by 10 cm, that is, 9a – 4a = 10.

Let’s find a:

5a = 10;

a = 2.

We calculate the lengths of the sides of the triangle:

4a = 4 * 2 = 8 (cm);

7a = 7 * 2 = 14 (cm);

9a = 9 * 2 = 18 (cm).

Let’s calculate the perimeter of the triangle:

P = 8 + 14 + 18 = 40 (cm).

Answer: the perimeter of the triangle is 40 cm.