Question

Периметр параллелограмма равен 21 см. найдите длины его смежных сторон, если известно, что одна из них в 2,5 раза длиннее другой.

Answer 1

3,5х=21/2
3,5х=10,5
х=10,5/3,5
х=3 - первая сторона
2,5х=2,5*3=7,5  -вторая сторона

Answer 2

Perimeter of a Parallelogram

To find the lengths of the adjacent sides of a parallelogram, given that the perimeter is 21 cm and one side is 2.5 times longer than the other, we can use the formula for the perimeter of a parallelogram.

The formula for the perimeter of a parallelogram is:

Perimeter = 2(a + b)

where a and b are the lengths of the adjacent sides.

Let's assume that one side of the parallelogram is x cm. According to the given information, the other side is 2.5 times longer, so its length is 2.5x cm.

Using the formula for the perimeter, we can write:

21 = 2(x + 2.5x)

Simplifying the equation:

21 = 2(3.5x)

21 = 7x

Dividing both sides of the equation by 7:

x = 3

Therefore, one side of the parallelogram is 3 cm, and the other side is 2.5 times longer, which is 7.5 cm.

So, the lengths of the adjacent sides of the parallelogram are 3 cm and 7.5 cm.