Properties of quadrilaterals · Year 9
In Year 9 you learn: proving properties.
A quadrilateral is any four-sided shape. Squares, rectangles, rhombuses, parallelograms, trapeziums and kites each have their own properties of sides, angles, diagonals and symmetry, which help us name them and find missing angles.
Key facts
- Rhombus: a parallelogram with four equal sides; diagonals cross at right angles.
- Rectangle: four right angles; diagonals equal. A square is both a rectangle and a rhombus.
Worked examples
Example 1
Three angles of a quadrilateral are 85°, 110° and 72°. Find the fourth angle x.
Answer: x = 93°