Steply

Slice a cone parallel to the base

Step by step, with the reason for every step · Cross sections · Geometry

Step by step

The question

Question: what shape is the cut, if we slice a cone parallel to the base?

cone, cut parallel to the base

A cross section is the flat face we see when we slice a solid.

cross section = the face of a cut

1 Look at the cut

Here is the cone.

We slice it parallel to the base.

The red face is the cut.

2 Name the shape

Flat, the cut looks like this.

Parallel to the base, the cut is round like the base, but smaller.

So it is a circle.

= cut: a circle

Careful!

A cut parallel to the base always has the shape of the base.

Careful: parallel cut = the base shape

3 Check

Let's check: a cut parallel to the base has the shape of the base.

So the answer is right!

like the base: circle

Let's look back.

First: look at the cut.

Then: name the shape.

Last: check.

Answer
Careful: parallel cut = the base shape

Your turn

Try this one yourself, then check:

square pyramid, cut through the top, up and down
Show the answer
a triangle

More from Cross sections

The whole lesson: Cross sections →