The side of the parallelogram is 2: 5, and its perimeter is 140 cm. Find the sides of the parallelogram.

From the condition it is known that the sides of the parallelogram are 2: 5. And also its perimeter is 140 cm. In order to find the sides of the parallelogram, we will compose and solve the equation.

But first of all, let’s introduce the similarity coefficient k. Then we write the smaller side as 2k, and the larger as 5k.

The formula for finding the perimeter of a parallelogram looks like this:

P = 2 (a + b);

Let’s make the equation:

2 (2k + 5k) = 140;

2k + 5k = 140: 2;

7k = 70;

k = 70: 7;

k = 10.

So, the length of the smaller side is 2 * 10 = 20 cm, and the larger side is 5 * 10 = 50 cm.