Quadrilateral: calculations, metric relationships.

Quadrilaterals have four sides and four angles. Calculating their perimeter is always the sum of the side lengths. The area can be found using different formulas depending on the type of quadrilateral, or by dividing the shape into triangles.

Important properties

• Perimeter: $P = a + b + c + d$ for sides $a, b, c, d$.

• Area of rectangle: $A = ext{length} imes ext{width}$.

• Area of parallelogram: $A = ext{base} imes ext{height}$.

• Area of trapezium: $A = \frac{1}{2}(a + b)h$, where $a$ and $b$ are the lengths of the parallel sides and $h$ is the height.

• For general quadrilaterals, area can be found by dividing into two triangles along a diagonal.