2-D shapes are flat
A square and a triangle can be drawn on paper because they are flat shapes.
4 equal sides4 corners
3 sides3 corners
Look for the number of sides and corners.
Year 3
Draw 2-D shapes and make 3-D shapes using modelling materials
Draw common 2-D shapes accurately and describe how 3-D shapes can be made with faces, edges and vertices.
Lesson overview
Geometry - properties of shape
2-D shapes are flat. They have sides and corners. 3-D shapes are solid. They have faces, edges and vertices, and they can be made from nets or modelling materials.
Polygons and quadrilaterals
A polygon is a closed 2-D shape with straight sides. A quadrilateral is a polygon with 4 sides.
4 straight sidesa quadrilateral
4 straight sidesa quadrilateral
5 straight sidesa polygon, not a quadrilateral
Count the straight sides: 4 sides make a quadrilateral.
3-D shapes are solid
A cube is a solid shape you can hold. It has square faces.
6 faces12 edges
6 faces8 vertices
3-D shapes take up space, unlike 2-D shapes.
Making a 3-D shape
Squares can be joined to make a cube.
Faces join together along edges.
Worked example
How do you know a cube is 3-D and a square is 2-D?
flat shape
solid shape
- A square is flat and can be drawn on a page.
- A cube is solid and has faces that join together.
- The square has sides and corners.
- The cube has faces, edges and vertices, so it is 3-D.
Try it
Decide first whether the shape is flat or solid, then use its properties to describe it.
Question 1
Which shape is 2-D?
Question 2
Which shape is 3-D?
Question 3
How many sides does a triangle have?
count the sides
Question 4
What do we call the flat surfaces on a 3-D shape?
Question 5
Which statement is correct?
Common mistakes
Watch for these when working through the lesson.
- Calling a cube a square because one face is a square.
- Mixing up edges and vertices.
- Thinking all 3-D shapes have the same faces.
Related topics
These ideas fit closely with this lesson.
- Recognise 3-D shapes in different orientations and describe them.
- Identify horizontal and vertical lines and pairs of perpendicular and parallel lines.