### 2D Shapes

2D means **flat**.

2D shapes only have two dimensions, **width and height**.

There are **3 main groups** of 2D shapes:

Triangles have **3 sides**.

Quadrilaterals have **4 sides**.

Polygons have more than **4 sides**.

Within each of these groups are more specific shape names to learn.

### Parallel Lines

Parallel lines are **straight lines** that run in exactly the **same direction**.

Parallel lines will **never cross each other** no matter how long you keep on drawing them – they will always **stay the same distance apart** and run in the **same direction** as each other.

They are sometimes indicated with a special **sign** that sits on both of the parallel lines, it looks like this:

>

Here is a rectangle with **2 pairs** of parallel sides:

You can see that one pair of parallel sides are marked with a **single >**, the other pair are marked with a **double >>**. This is so you can tell which are sides parallel.

### Quadrilaterals

**Quadrilaterals** all have **4 sides**.

Here are the different types of quadrilateral shapes for you to learn.

Square

All sides are **equal in length** and the corners are **all right angles**.

Rhombus

A rhombus looks like a square that has been pushed over to one side. It’s sides are **all equal lengths** and are **parallel** with the opposite side.

Rectangle

Similar to a square but made up of **two pairs** of equal length sides. **All corners are right angles** and sides run parallel with the opposing side.

Parallelogram

A parallelogram is a rectangle that has been pushed over to the side. It has **two pairs of opposite sides** that are **equal in length and parallel**.

Trapezium

A Trapezium has **one pair of parallel sides**, it’s other two sides are not parallel.

Kite

A kite has **no parallel sides**. It is made up of two pairs of equal length sides that are **next to each other**.

### Triangles

Triangles all have **3 sides**.

There are **four** to learn:

Right-angle triangle

A right angle triangle is easy to spot, it has one angle that is a **right angle**.

Equilateral Triangle

These triangles have **3 sides of equal length** and all **3 angles are equal**.

Isosceles Triangle

**2 Sides** are equal in length, and **two angles** are equal.

Scalene Triangle

All 3 sides are **different** lengths and all 3 angles are **different**.

### Polygons

Polygons are shapes with **more than 4 sides**.

**Irregular polygons** have sides of **different lengths**.

**Regular polygons** have sides that are **all equal in length**.

Here are some polygons to learn:

Pentagon

Pentagons have **five sides**.

Regular pentagon:

Irregular pentagon:

Hexagon

Hexagons have **six sides**.

Regular hexagon:

Irregular hexagon:

Heptagon

Heptagons have **seven sides**.

Regular heptagon:

Irregular heptagon:

Octagon

Optagons have **eight sides**.

Regular octagon:

Irregular octagon:

### Symmetry

A **line of symmetry** is a line that we can draw on a shape and on each side of this line the shape is an **identical reflection** of the other side.

2D shapes can have **no lines of symmetry**, **one line of symmetry** or **several lines of symmetry**.

Here is an example of a line of symmetry on a **kite**:

If we were to **fold the shape in half** over this line the right side and left side would **fit exactly on top of each other**.

This **irregular pentagon** has no lines of symmetry:

This **equilateral triangle** has **3 lines of symmetry**: