The sides of the triangle are 5: 3: 7. Find the sides of a similar triangle with a perimeter of 45 cm.

From the condition, we know that the sides of the triangle are 5: 3: 7. In order to find the sides of a similar triangle with a perimeter of 45 cm, let’s enter the coefficient of similarity x and use it to write the sides of the rectangle as:

5x; 3x and 7x.

Let’s remember the formula for finding the perimeter of a rectangle.

P = a + b + c, where a, b and c are the sides of the triangle.

Let’s write down the equation and solve it:

5x + 3x + 7x = 45;

15x = 45;

x = 45: 15;

x = 3.

Find the sides of the triangle:

5 * 3 = 15 cm; 3 * 3 = 9 cm; 7 * 3 = 21 cm.