Area of a Trapezoid

Submitted by Isoscel on Sat, 01/05/2008 - 05:41.

The area of a trapezoid is the equal with half of the sum of the parallel sided multiplied by the height of the trapezoid.

$Area(ABCD) = \frac{(BC+AD)h}{2}$

Proof:

Let us consider the two triangles: ABD and BDC. They have the the same height as the trapezoid.

$Area(ABCD) = Area(ABD) + Area(BDC) =$

$= \frac{AD \cdot h}{2} + \frac{BC \cdot h}{2} = \frac{(AD+BC) h}{2}$