Monday, September 24, 2012

Deriving the Area of Trapezoids

Given below is a trapezoid with bases b1 and b2 and height h. Move the slider to the extreme right and observe what happens.  This is a Java Applet created using GeoGebra from - it looks like you don't have Java installed, please go to

Guillermo Bautista, Created with GeoGebra


  1. When alpha is 180 degrees, what shape is formed? Justify your answer. 
  2. How is the area of the shape in 1 computed based on the given? 
  3. What is the relationship between the area of the shape in 1 and the area of the trapezoid?
  4. What formula will describe the area of the trapezoid based on the given above?