Step by step
The question
Question: find the volume of a pyramid with a rectangle base 10 by 6 and height 9.
1 Area of the base
The base is a rectangle, 10 by 6.
Its area is length times width: A = 10 × 6.
10 times 6 is 60.
So the base is A = 60 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 = 60 and height = 9.
Keep the numbers small: divide 60 by 3 first.
60 divided by 3 is 20.
So V = 20 × 9.
20 times 9 is 180.
So the volume is 180 cubic units.
Let's look back.
First: area of the base.
Last: a third of the box.