Volume of pyramid square base 1.5 height 4

Step by step

The question

Question: find the volume of a pyramid with a square base 1.5 by 1.5 and height 4.

1 Area of the base

The base is a square, 1.5 by 1.5.

Its area is side times side: A = 1.5 × 1.5.

Forget the points: 15 times 15 is 225.

Together, the numbers have 1 + 1 = 2 digits after the point.

So the answer has 2 too: 2.25.

So the base is A = 2.25 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 = 2.25 and height = 4.

2.25 times 4 is 9.

9 divided by 3 is 3.

So the volume is 3 cubic units.

Let's look back.

First: area of the base.

Last: a third of the box.