Irregular quadrilaterals
Kite
A A kite has two pairs of adjacent sides with equal lengths, like two isosceles triangles with their bases joined. is made up of two isosceles triangles joined base to base.
Its diagonals are not equal but the longer one cuts the shorter in half at \(90^\circ\).
The longer diagonal is a line of symmetry.
Question
For this kite we are given an angle of \(40^\circ\). What is the value of \(y^\circ\)?
Using the vertical line of symmetry, the opposite angle is \(40^\circ\).
Now using the right-angled triangle:
\(y^\circ = 180^\circ - (90^\circ + 40^\circ ) = 180^\circ - 130^\circ = 50^\circ\)
Rhombus
A A rhombus is a parallelogram with equal sides. has four equal sides and also has its opposite sides parallel. It is formed by joining two identical isosceles triangles base to base.
Its diagonals are not equal but cut each other in half at right angles. Both diagonals are lines of symmetry.
Parallelogram
A A parallelogram has opposite sides which are both parallel and equal in length. has opposite sides which are equal and parallel. The opposite angles are also equal.
The diagonals are not equal and are not lines of symmetry.
