The Law of Sines (sine law, sine formula, or sine rule) is an equation relating the lengths of the sides of an arbitrary triangle to the sines of its angles.[br][br]Drag the points to adjust side length and angle measure. Click the check boxes to show the ratio of the sine of the angle to the measure of length of the opposite side.[br][br][math] \frac {sin \alpha}{a} = \frac {sin \beta}{b} =\frac {sin \gamma}{c} = 2R[/math] [br] [math]\frac {a}{sin \alpha} = \frac {b}{sin \beta} =\frac {c}{sin \gamma} = \frac {1}{2R} [/math][br][br]R is the radius of the circle which circumscribes the trangle ABC.

Inspired by applets created by Adam Caudell and Daniel Mentrard, thanks.[br][url]http://www.geogebratube.org/student/m26316[/url][br][url]http://web.psjaisd.us/auston.cron/ABCronPortal/GeoGebraMenu/GeogebraFiles/trigonometry/trigFr/Trigorequel3sin2.html (English translation of Daniel's French version)[/url]