Step by step
The question
Question: find the volume of a pyramid with a square base 6 by 6 and height 4.
1 Area of the base
The base is a square, 6 by 6.
Its area is side times side: A = 6 × 6.
6 times 6 is 36.
So the base is A = 36 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 = 36 and height = 4.
Keep the numbers small: divide 36 by 3 first.
36 divided by 3 is 12.
So V = 12 × 4.
12 times 4 is 48.
So the volume is 48 cubic units.
Let's look back.
First: area of the base.
Last: a third of the box.