The width of the rectangle is 5/7 of its length. Find the sides of a rectangle if its area is 35 dm2.

The length of the rectangle (a) -? dm;

The width of the rectangle (b) is? dm, which is 5/7 of a;

The area of the rectangle (Sp.) Is 35 dm ^ 2.

It is known that the area of a rectangle is calculated by the formula:

Sp. = a * b.

By the condition b = 5/7 * a (dm), which means, substituting this into the formula for finding the area, we get:

a * 5/7 * a = 35;

a ^ 2 = 35: 5/7;

a ^ 2 = 49;

a = ± 7;

a = 7, because the length value cannot be negative.

Find the width of the rectangle: b = 5/7 * 7 = 5 (dm).

Answer: the length of the rectangle is 7 dm, the width is 5 dm.