Geometry

A quadrilateral is any four sided shape. The strange, long name comes from Latin: Quad, meaning four, and Lateral, meaning side (four-side).

There are 6 different types of quadrilateral:

Square
- 4 equal length sides
- 4 right angles
- 2 pairs of parallel sides

Rhombus
- 4 equal length sides
- 2 pairs of equal opposite angles
- 2 pairs of parallel sides

Parallelogram
- 2 pairs of equal opposite angles
- 2 pairs of parallel sides

Trapezium
- 1 pair of parallel sides
- a regular trapezium has 2 pairs of adjacent equal angles (that are not right angles)

Kite
- no parallel sides
- 2 pairs of adjacent equal length sides
- the angles at which these pairs meet are equal and opposite
- diagonals meet at a right angle and bisect the opposite vertice

- do not fit in any of the above!

Notice: A square is a special type of rhombus, a rhombus is a special type of parallelogram!

Important: ‘Diamond’ is *not* a mathematical name. What people call a diamond is either just a square rotated by 45 degrees, or a rhombus. In primary school, a rectangle will have sometimes been referred to as an oblong. A rectangle *can* be a square (i.e. all squares are also rectangles), whereas an oblong is specifically a rectangle with only two lengths the same i.e. not a square. Oblongs are rarely mentioned at secondary school level.

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