2D shapes
🎯 In this topic you will
- Describe and sort 2D shapes using the number of sides.
- Determine how many sides different 2D shapes have.
- Compare shapes by identifying similarities and differences.
- Use the correct mathematical names for common 2D shapes.
- Identify, describe, and sort a range of 2D shapes.
- Recognize when a 2D shape looks the same after being rotated.
- Explain similarities and differences between 2D and 3D shapes.
🧠 Key Words
- 2D
- circle
- curved
- straight
- triangle
- square
- rectangle
- pentagon
- hexagon
- rotate
Show Definitions
- 2D: A flat shape that has only length and width, with no thickness.
- circle: A 2D shape with one continuous curved edge and no corners.
- curved: A line or edge that bends smoothly without sharp corners.
- straight: A line or edge that does not bend and goes directly from one point to another.
- triangle: A polygon with three straight sides and three corners.
- square: A four-sided shape with equal sides and four right angles.
- rectangle: A four-sided shape with opposite sides equal and four right angles.
- pentagon: A polygon that has five straight sides.
- hexagon: A polygon that has six straight sides.
- rotate: To turn a shape around a fixed point without changing its size or shape.
📐 2D Shapes Are Flat
2D shapes are flat. This is what makes them different from 3D shapes.
🧩 Learning Through Shape Patterns
Playing with shapes and making patterns using 2D shapes will help you to learn much more about them.
❓ EXERCISES
1.
👀 Show answer
2. A circle has curved sides
A square has straight sides
Draw a ring around the correct word in each sentence
a. A rectangle has $4$ curved / straight sides.
b. A triangle has $1$ / $2$ / $3$ / $4$ straight sides.
👀 Show answer
b. $3$
3. Match each shape to the correct clouds.Are the sides straight or curved?Count the shapes for each cloud.Keep asking your partner questions until they work out what each shape is.Write the number in these boxes.
👀 Show answer
Curved shapes are the circles.
Count the number of each group from the picture.
4. Use shape pieces to draw a rocket.Use as many of each shape as you want.How many shapes did you use?How is your partner’s rocket the same?How is it different?
👀 Show answer
🧠 Think like a Mathematician
You will need a set of shapes.
Method:
- Put your shapes in a bag or a box.
- Pick a shape without looking at it.
- Ask questions to find out what shape it is.
- Try questions like: “How many sides does it have?” and “Are the sides straight or curved?”
- Say what shape you think it is.
- If your guess is correct, choose another shape and repeat.
Follow-up Questions:
Show Answers
- 1: Counting sides helps you narrow down which shape it could be, because each shape has a specific number of sides (for example, a triangle has $3$ sides and a square has $4$).
- 2: Knowing whether sides are straight or curved helps you distinguish between shapes such as circles (curved) and polygons like squares and triangles (straight).
🔄 Rotating Shapes to Make Patterns
Playing with and making patterns using 2D shapes will help you to learn much more about them. Make a pattern using the same shape but turning it around. We can rotate the shape.
🧱 Shapes That Fit Together
Some 2D shapes fit together with no spaces. Some 2D shapes will always have spaces between them. This is important when you want to make patterns for buildings, floors or sewing.
👀 Same Shape When Turned
Some shapes look different when they are turned around, but they are still the same shape.
❓ EXERCISES
1. Draw a ring around the triangles.
There are ______ triangles.
There are ______ shapes that are not triangles.
👀 Show answer
There are $9$ shapes that are not triangles.
2. Big triangles can be made by using lots of small triangles.
Use just $2$ colours to make your own triangle pattern.
👀 Show answer
3. Play this game with a partner.You are trying to make squares.Take turns to spin the spinner.Take that number of sticks to make a square.You may not have enough or you may have too many.The first person to make $4$ squares is the winner.You can make other shapes.
👀 Show answer
4. Put together two squares to make a new shape.
How many different shapes or patterns can you make with two squares?
Draw $2$ different ones that you can make.
👀 Show answer
5. Draw around a face of the $3$D shape.
Then draw a ring around the shape of the face.
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• Cube → square
• Cylinder → circle
• Cuboid → rectangle
🧠 Think like a Mathematician
You will need lots of triangles.
Method:
- Make a star shape using some triangles.
- Try to create different star shapes.
- Look at examples and then design your own.
- Experiment by turning and arranging the triangles in new ways.
Follow-up Questions:
Show Answers
- 1: Answers will vary. You can often make several different star shapes by rotating and rearranging the triangles.
- 2: Possible shapes include larger triangles, hexagon-like shapes, diamonds, or other patterns made from the same pieces.
- 3: Using different types of triangles can change the star’s size, symmetry, and angles, creating new and interesting designs.
❓ EXERCISES
6. For each shape, tick if it is a $2$D shape or a $3$D shape.
👀 Show answer
$2$D shapes: circle, rectangle, triangle, square.
A $2$D shape is flat. A $3$D shape has depth.