SOLUTION: In ∆ABC, if the lengths of a, b, and c are 22.5 centimeters, 18 centimeters, and 13.6 centimeters, respectively, what are m B and m C to two decimal places?

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Question 894153: In ∆ABC, if the lengths of a, b, and c are 22.5 centimeters, 18 centimeters, and 13.6 centimeters, respectively, what are m B and m C to two decimal places?
Answer by Theo(13342) About Me  (Show Source):
You can put this solution on YOUR website!
you can solve this using c^2 = a^2 + b^2 - 2*a*b*cos(C) formula.
that will get you angle C.
you can then find angle B using b^2 = a^2 + c^2 - 2*a*c*cos(B) formula.
you can also find angle B using c/sin(C) = b/sin(B) formula.

the first and second formulas are the law of cosine formulas.
the third formula is the law of sines formula.

both formulas are very useful to find angles and sides in triangles that are not right triangles.

your solution for angle C will be 37.18820916 degrees.

your solution for angle B will be 53.12893209 degrees.

your solution for angle A will be 89.68285875 degrees.

once you found angle B and and C, angle A is simply 180 degrees minus their sum.

here's a reference on law of cosines.

http://www.mathsisfun.com/algebra/trig-cosine-law.html

here's a reference on law of sines.

http://www.mathsisfun.com/algebra/trig-sine-law.html