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Joel's SAS Formula

Goal: find all the angles and sides of an SAS triangle using only the Law of Sines.

Explanation

Download Joel's SAS Formula.gsp to play around with it in the Geometer's Sketchpad.

Formula

This differs from the formula at the top because 180° needs to be added when the value is negative because tan
LaTeX: A=(tan^{-1}(\frac{sinB}{\frac{c}{a}-cosB})+180°) \bmod 180° in any triangle ABC.

Derivation