Step by step
The question
Question: what shape is the cut, if we slice a square pyramid through the top, up and down?
A cross section is the flat face we see when we slice a solid.
1 Look at the cut
Here is the square pyramid.
We slice it through the top, up and down.
The red face is the cut.
2 Name the shape
Flat, the cut looks like this.
Up and down through the top: the cut is a triangle.
So it is a triangle.
Careful!
Not a square.
Only a cut straight across shows the square base.
3 Check
Let's check: look at the square pyramid from the side.
You see a triangle, the same as the cut through the middle.
So the answer is right!
Let's look back.
First: look at the cut.
Then: name the shape.
Last: check.