The perimeter of the rectangle is 20cm. The length is 5 times the width. Find the length and width of this rectangle.

The perimeter is straight. (Rpr) – 20 cm;

Length straight (but) – ? cm, 5 times more than b;

Width straight (b) -? cm.

Rpr = (a + b) * 2;

(a + b) * 2 = 20.

By condition, the length of the rectangle is 5 times its width, i.e. we can write the length value as b * 5 = 5b. Substituting this value into the perimeter formula, we get:

(5b + b) * 2 = 20;

6b * 2 = 20;

12b = 20;

b = 20: 12;

b = 5/3 (cm).

Now we can calculate the length of the rectangle: a = 5b = 5 * 5/3 = 25/3 (cm).

Answer: the length of the rectangle is 5/3 cm, and its width is 25/3 cm.