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2D shapes

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visibility 15update 2 days agobookmarkshare

🎯 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.

📘 Worked example

How many circles, squares and triangles are there?

Answer:

There are 4 circles.

There are 3 squares.

There are 5 triangles.

Squares have 4 sides. Triangles have 3 sides. A circle has one curved side.

Carefully count each shape in the picture. Grouping the same shapes together makes counting easier and helps avoid mistakes.

❓ EXERCISES

👀 Show answer

Colour all shapes that are circles, triangles, squares and rectangles using the colours shown. Check each shape carefully by counting its sides or looking for curved edges.

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

a. straight
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

Straight shapes are the squares and triangles.
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

Answers will vary. Count the shapes used in your rocket. Compare with your partner by checking which shapes you both used and which ones are different.

🧠 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:

1. How can counting sides help you identify a shape?

2. Why is it useful to know whether the sides are straight or curved?

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.

📘 Worked example

Draw lines from the shapes to the correct circles. Count how many 2D and 3D shapes there are.

Answer:

There are $4$ 3D shapes.

There are $4$ 2D shapes.

A 2D shape is flat and has only length and width. A 3D shape has depth as well.

Sort the shapes by checking whether they are flat or solid. Then count how many shapes are in each group.

❓ EXERCISES

1. Draw a ring around the triangles.

There are ______ triangles.
There are ______ shapes that are not triangles.

👀 Show answer

There are $6$ triangles.
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

Answers will vary. Use exactly $2$ colours and fill the small triangles to create a repeating pattern.

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

Answers will vary. A square needs $4$ equal sticks. The winner is the first player to make $4$ squares.

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

Answers will vary. Examples include placing the squares side by side or one above the other.

5. Draw around a face of the $3$D shape.
Then draw a ring around the shape of the face.

👀 Show answer

Match each $3$D shape to its face:
• 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:

1. How many different star shapes can you make?

2. What other shapes can you make?

3. What happens if you use different types of triangles together to make a star?

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

$3$D shapes: sphere, cube/cuboid.
$2$D shapes: circle, rectangle, triangle, square.

A $2$D shape is flat. A $3$D shape has depth.

📘 What we've learned

We learned that $2$D shapes are flat, while $3$D shapes have depth.
We practiced describing and sorting shapes by counting sides and noticing curved or straight edges.
We used the correct names for common shapes such as triangle, square, rectangle, pentagon and hexagon.
We explored how shapes can be rotated and still remain the same shape.
We discovered that some $2$D shapes fit together with no gaps, which helps when making patterns.
We compared $2$D and $3$D shapes by looking at their faces and properties.

2D shapes

🎯 In this topic you will

🧠 Key Words

📐 2D Shapes Are Flat

🧩 Learning Through Shape Patterns

❓ EXERCISES

🧠 Think like a Mathematician

🔄 Rotating Shapes to Make Patterns

🧱 Shapes That Fit Together

👀 Same Shape When Turned

❓ EXERCISES

🧠 Think like a Mathematician

❓ EXERCISES

📘 What we've learned

Related Past Papers

Related Tutorials

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