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 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 all have 4 sides.
Here are the different types of quadrilateral shapes for you to learn.
All sides are equal in length and the corners are all right angles.
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.
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.
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.
A Trapezium has one pair of parallel sides, it’s other two sides are not parallel.
A kite has no parallel sides. It is made up of two pairs of equal length sides that are next to each other.
Triangles all have 3 sides.
There are four to learn:
A right angle triangle is easy to spot, it has one angle that is a right angle.
These triangles have 3 sides of equal length and all 3 angles are equal.
2 Sides are equal in length, and two angles are equal.
All 3 sides are different lengths and all 3 angles are different.
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:
Pentagons have five sides.
Hexagons have six sides.
Heptagons have seven sides.
Optagons have eight sides.
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: