# Discovering the Law of Cosines

A triangle with sides a, b and c is drawn in the left hand panel. A regular
polygon of n sides is erected on each side of the triangle.
Use the blue dot in the left hand panel to adjust the ratio of b to a.
Use the gold dot to vary the shape of the triangle. [You can animate
the shape of the triangle by clicking on the icon in the lower left hand corner of either panel.]
You can change the polygon erected on each side of the triangle by
using the polygon slider.

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