Students: This applet is to be used when trying to use coordinate geometry prove two triangles (drawn in the coordinate plane) congruent. You already know how to calculate the distance between any two points in the coordinate plane, so finding the length of any side of a triangle should be an easy task.
However, calculating the measure of an interior angle between two sides of a triangle is a bit more complicated.If you need to calculate the angle measure between any two sides of a triangle, follow the directions in the applet below: