Area of a quadrilateral

A quadrilateral is a polygon with four sides. The area of a quadrilateral depends on its type. For simple quadrilaterals, there are formulas:

• Rectangle: $A = ab$ (where $a$ and $b$ are side lengths)
• Parallelogram: $A = bh$ (base $b$, height $h$)
• Trapezium: $A = \frac{1}{2}(a + b)h$ (parallel sides $a$, $b$, height $h$)

For any convex quadrilateral, you can draw a diagonal to split it into two triangles, find each area, and add them.

Important properties

• The area formula depends on the type of quadrilateral.

• Any convex quadrilateral can be divided into two triangles.

• For cyclic quadrilaterals, Brahmagupta's formula can be used.