Volume of pyramid base 2.5 by 6 height 4

Step by step

The question

Question: find the volume of a pyramid with a rectangle base 2.5 by 6 and height 4.

1 Area of the base

The base is a rectangle, 2.5 by 6.

Its area is length times width: A = 2.5 × 6.

Forget the points: 25 times 6 is 150.

The numbers have 1 digit after the point.

So the answer has 1 too: 15.0, which is 15.

So the base is A = 15 square units.

2 A third of the box

Draw a box around the pyramid, with the same base and the same height.

Fill the pyramid with sand 3 times.

That fills the box exactly.

So the pyramid is one third of the box.

The box is A times height.

So the pyramid is V = ⅓ × A × height.

Now put the numbers in: A = 15 and height = 4.

Keep the numbers small: divide 15 by 3 first.

15 divided by 3 is 5.

So V = 5 × 4.

5 times 4 is 20.

So the volume is 20 cubic units.

Let's look back.

First: area of the base.

Last: a third of the box.