Compare flat shapes
Look closely at the sides of each shape.
3 sides3 corners
4 equal sides4 corners
4 sides2 long, 2 short
The number and type of sides help us name each shape.
Year 2
Identify and describe the properties of 2-D shapes, including the number of sides and line symmetry in a vertical line
Describe flat shapes by their sides and notice simple vertical symmetry.
Lesson overview
Geometry - properties of shape
A 2-D shape is a flat shape. We can describe 2-D shapes by counting sides and corners. Some shapes also have a vertical line of symmetry, which means the left and right sides match if the shape is folded down the middle.
Count the sides
A pentagon has 5 sides. A hexagon has 6 sides.
5 sides5 corners
6 sides6 corners
The shape name often helps us remember how many sides it has.
Vertical symmetry
A square can have a vertical line of symmetry because both sides match.
matches on both sides
can fold down the middle
Symmetry is about matching parts, not only counting sides.
Worked example
How do we know this shape is a pentagon?
12345 sides
- Look at the flat shape carefully.
- Count the sides one by one.
- There are 5 sides.
- A 5-sided shape is called a pentagon.
Try it
Count sides carefully and use the shape properties to choose the answer.
Question 1
Which shape has 3 sides?
3 sides
4 sides
6 sides
Question 2
Which shape has 4 equal sides?
4 sides
4 equal sides
curved edge
Question 3
How many sides does a pentagon have?
Question 4
Which shape has no straight sides?
straight sides
curved edge
straight sides
Question 5
Which statement is correct?
Common mistakes
Watch for these when working through the lesson.
- Counting corners twice or missing one side.
- Calling any four-sided shape a square.
- Forgetting that a circle has no straight sides.
Related topics
These ideas fit closely with this lesson.
- Identify and describe the properties of 3-D shapes, including the number of edges, vertices and faces.
- Compare and sort common 2-D and 3-D shapes and everyday objects.