The volume of a rectangular parallelepiped is 640, the width is 2 times less than the length

The volume of a rectangular parallelepiped is 640, the width is 2 times less than the length, the height is 5/2 of the length. What is the width, length, height?

Let’s say that the width of the rectangular parallelepiped is x cm.

Since it is 2 times less than the length, then the length of the figure will be equal to: 2 * x cm.

Thus, the height will be: 5/2 * 2 * x = 5 * x cm.

The parallelogram volume will be:

x * 2 * x * 5 * x = 640.

10 * x ^ 3 = 640.

x ^ 3 = 640/10.

x ^ 3 = 64.

3√ = 4 cm (width).

2 * x = 2 * 4 = 8 cm (length).

5 * x = 5 * 4 = 20 cm (height).

We check the solution to the problem:

4 * 8 * 20 = 640 cm3

Answer: The sizes of the figure are 4, 8 and 20 cm.