This activity is a based on an activity I saw in Exploring Geometry with the Geometer's Sketchpad. Student will construct a trapeziod and then use rotation to create a parallelogram from the trapeziod. The follow up questions lead the student to derive the formula for the area of a trapeziod. This activity really only takes one 45 minute class period and the students seem to have a better understanding of area after completing the activity.