The sides of the rectangle are 4: 5, find the perimeter of the rectangle if the large side is 8.

1. If the large side of the rectangle is 5 parts, we find the length of one part:

8/5 = 1.6.

2. Knowing the length of one part, you can easily find the length of the smaller part of the rectangle:

1.6 x 4 = 6.4.

3. It remains to calculate the perimeter of the rectangle. It is equal to the sum of twice the larger side and twice the smaller side:

2 x 8 + 2 x 6.4 = 28.8.

Answer: The perimeter of this rectangle is 28.8.