The rectangle is 42 cm wide, which is 3/14 of its perimeter. Find the length of this rectangle.

The perimeter of a rectangle is twice the sum of its two adjacent sides. P = 2 * (a + b), where a – length, b – width. To find a number by its fractional part, you need to divide this number by a fraction. We calculate what the perimeter of the rectangle is, knowing that 3/14 of it is 42 cm.

P = 42: 3/14 = 42 * 14/3 = 196 cm.

Let’s calculate what the length of the rectangle is.

(a + 42) * 2 = 196;

a + 42 = 196/2;

a + 42 = 98;

a = 98 – 42;

a = 56.

Answer: 56 cm.