Find all the solutions of the following triangle using the Law of Sines.

Question

Angle A: 83°20'
Angle C: 54.6°
c: 18.1

How would I find I find angle B? I know that you would subtract angle A and C from 180, but I do not understand how to maintain the minutes (') on my calculator.

Answer 1

You could always punch in

1/3 + 83 sin

to get sin of 83 1/3 degrees.

Or, just get sin 83.333333333 degrees. It should be close enough.

So, assuming you can in fact evaluate your sines, just use the fact that

A+B+C = 180°
so, B = 180° - 83°20' - 54°36' = 42°4' = 42 1/15 ° = 42.06666666°

b/sinB = c/sinC
b = csinB/sinC = 18.1(.67)/.815 = 14.88