# Basic 2D shapes

2-dimensional (2D) shapes have only two dimensions, length and width.

### Here are some basic regular 2D Shapes :

A rectangle has 4 sides (quadrilateral) and 4 right angles, its opposite sides are equal, and they are parallel to each other and it has 2 lines of symmetry and rotational symmetry order 2.

To calculate the area of a rectangle, multiply its length by its width (The answer will be a square measure, for example: cm2)

To calculate the perimeter of a rectangle, add up the length of all sides.

Square has 4 equal sides (quadrilateral) and 4 right angles, it has 2 pairs of parallel sides, it has 4 lines of symmetry and 4 rotational symmetry.

To calculate the area of a square, multiply its length by its width (The answer will be a square measure, for example: cm2)

To calculate the perimeter of a rectangle, add up the length of all sides or you can multiply the length of one side by 4 as the length of all sides equal.

A circle has no sides and no angles -as you see.
All points on the edge of the circle are at the same distance from the centre.

A circle has infinite number of line of symmetry and infinite order of rotational symmetry.

The distance from the centre to the all point on the edge called radius (plural : radii) and the whole line from edge to another called diameter.
To find out the diameter of a circle just double the radius (radius * 2)

The perimeter of a circle called “circumference” which is the whole line around the circle.

To find out the circumference of a circle we use this formula : C = π d
π = 22/7 ≈ 3.14
d = The diameter of the circle