Explore · Mathematics · Geometry

3-D shapes (age 5+)

Analyse and compare 2-D and 3-D shapes using informal language to describe sides, vertices, and other attributes

ages 5 to 68 practice questionsvideo included

What a learner can do afterwards

Count the sides and corners of a shape
Compare a triangle and a rectangle by number of sides
Describe a cube as having 'square faces' and 'corners'

The lesson

Every shape has sides and corners you can count. A side is a straight edge. A corner is where two sides meet.

This triangle has 3 sides and 3 corners.

Try it together

A triangle has 3 sides. A rectangle has 4 sides. The rectangle has one more side than the triangle.

Good to know

Look for flat square faces to find a cube. A cube also has sharp corners you can feel.

Count sides and corners to tell shapes apart.

Watch it

Where it sits

Learn first

2-D shapes 3-D shapes

This opens up

Building & Drawing Shapes Angles in triangles (age 6+)Edges, vertices, and faces 2-D shapes (age 6+)Combining Simple Shapes

Where this leads

Jobs that lean on this skill. Follow one to see everything it is built on.

Interior Designer Air Traffic Controller Artist Cartographer Civil Engineer Graphic Designer

Then practise

8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.