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gryder
Apr 26, 2004, 10:09 PM
Can someone tell me how to solve for the angles of a triangle, when all three sides are known, but all angles are un-known..

Any help appreciated.

Don Gryder

reinsuranc
Dec 13, 2005, 05:06 PM
Let a, b, and c be the lengths of the legs of a triangle opposite angles A, B, and C. Then the law of cosines states

a^2 = b^2+c^2-2bccosA
b^2 = a^2+c^2-2accosB
c^2 = a^2+b^2-2abcosC.

Solving for the cosines yields the equivalent formulas
cosA = (-a^2+b^2+c^2)/(2bc)
cosB = (a^2-b^2+c^2)/(2ac)
cosC = (a^2+b^2-c^2)/(2ab).

Greek2Me
Sep 25, 2009, 04:38 PM
Check out these articles for a simple tool and tutorial that will make trig simple enough for ANYBODY to do!

How to Pass That Trigonometry Exam (Without Losing Your MIND!) Part II - Unknown Angles | eHow.com (http://www.ehow.com/how_5428511_pass-part-ii-unknown-angles.html)

How to Pass That Trigonometry Exam (Without Losing Your MIND!) Part I - Unknown Sides | eHow.com (http://www.ehow.com/how_5227490_pass-mind-part-unknown-sides.html)

Greek2Me
Oct 16, 2009, 09:55 AM
Sorry, duplicate