Find the volume of a rectangular parallelepiped if its length is 21 cm, and its width is 3/7

Find the volume of a rectangular parallelepiped if its length is 21 cm, and its width is 3/7 of the length and 30% of the height.

Let’s find the width of the parallelepiped. It is 3/7 of the length, and the length is 21 cm.

x = 21 cm * 3/7.

x = 9 cm. Width is 9 cm.

The width is known to be 30% of the height. Let’s find the height.

y = 9 cm ÷ 30% * 100%.

y = 30 cm. The height is 30 cm.

Let’s find the volume of a rectangular parallelepiped.

21 cm * 9 cm * 30 cm = 5670 cm³.

Answer: 5670 cm³.