Triangles in a Trapezoid
The diagonals of a trapezoid divide the interior region into four nonoverlapping triangles. What is the relationship between the areas of the green triangles (the triangles that share a side with the legs)? What is the relationship between the areas of the yellow triangles (the triangles that share a side with the bases)? You may need to make additional measurements other than the area of the triangles. Explain your solutions.

Related External Resources 
Heron's Area of a Triangle
This site will take you through some historical explorations, some interactive activities, and some intriguing connections in mathematics.
Geoboards in the Classroom
This unit deals with the side lengths and area of twodimensional geometric figures using the geoboard as a pedagogical device.
Java explorations (many) [ java applet ]
Explore the Pythagorean Theorem and the Minimum distance problem.
Submit your idea for an investigation to InterMath.
