The width of the rectangle is 4.1 \ 5 cm, which is 7 \ 10 of its length. Find the perimeter of the rectangle.

1. For convenience, we represent the width of the rectangle as a decimal fraction:

4 1/5 = 4.2 (cm).

7/10 of the length can also be represented as a decimal fraction. It:

7/10 = 0.7.

2. If the width is 0.7 of the length, then we can easily calculate the length by proportion:

0.7 – 4.2;

1.0 – H.

Where from:

X = 4.2 x 1 / 0.7;

X = 6 (cm).

3. Knowing the length and width of the rectangle, you can easily find its perimeter:

2 x 6 + 2 x 4.2 = 12 + 8.4 = 20.4 (cm).

Answer: The perimeter of this rectangle is 20.4 cm.