Square faces
A cube has square faces.
solid shape
flat face on the surface
The whole shape is 3-D, but each flat face can be 2-D.
Year 2
Identify 2-D shapes on the surface of 3-D shapes
Spot flat 2-D shapes on the faces of 3-D solids.
Lesson overview
Geometry - properties of shape
Many 3-D shapes have flat faces. Those faces are 2-D shapes. For example, a cube has square faces and a cylinder has circular faces. Looking at the surface helps us spot the flat shape clearly.
Circular faces
A cylinder has circles on its flat ends.
solid shape
flat face on each end
Not every part of the surface is flat, so check the faces carefully.
Triangles on a pyramid
A pyramid can have triangular faces.
solid shape
sloping flat face
The face is 2-D even though the whole object is 3-D.
Worked example
What 2-D shape can you find on the face of a cuboid?
look at one flat face
the face shape
- Think about the flat faces on a cuboid.
- Each flat face is a 2-D shape.
- Those faces are rectangles.
- So a rectangle can be found on the surface of a cuboid.
Try it
Match the 3-D shape to the flat 2-D face you can see on it.
Question 1
What 2-D shape can you find on the face of a cube?
Question 2
What 2-D shape can you find on the end of a cylinder?
Question 3
Which 3-D shape can have triangular faces?
Question 4
What 2-D shape can you find on the face of a cuboid?
Question 5
Which statement is correct?
Common mistakes
Watch for these when working through the lesson.
- Naming the whole 3-D shape instead of the flat face.
- Choosing a face that does not appear on that solid.
- Forgetting that a curved surface is not the same as a flat face.
Related topics
These ideas fit closely with this lesson.
- Identify and describe the properties of 2-D shapes, including the number of sides and line symmetry in a vertical line.
- Identify and describe the properties of 3-D shapes, including the number of edges, vertices and faces.