Law Of Cosines

Drag the points A, B, and C to see the law of cosines verified for arbitrary triangles.

Sorry, the GeoGebra Applet could not be started. Please make sure that Java 1.4.2 (or later) is installed and active in your browser (Click here to install Java now)

If you think of the "-2*b*c*cos(Alpha)" as an error term for the Pythagorean Theorem in the non-right-angle case, what happens when angle Alpha > 90 degrees? Is the Pythagorean Estimate too small or too large in that case?

Dave Matthews, March 29, 2007, Created with GeoGebra