Wolfram Demonstrations Projecthttp://demonstrations.wolfram.com/An Open Resource of Interactive Mathematica VisualizationsCopyright 2009 Wolfram Demonstrations Project & ContributorsThe Areas of a Parallelogram and a Rectangle with the Same Base and Height Are Equalhttp://demonstrations.wolfram.com/TheAreasOfAParallelogramAndARectangleWithTheSameBaseAndHeigh/]]>http://demonstrations.wolfram.com/TheAreasOfAParallelogramAndARectangleWithTheSameBaseAndHeigh/Area of a Trianglehttp://demonstrations.wolfram.com/AreaOfATriangle/]]>http://demonstrations.wolfram.com/AreaOfATriangle/