Math CentralQuandaries & Queries


Question from Michael, a student:

I am supposed to solve for the length of side "b" of an irregular triangle. I am given the following:
Side a: 65'
Side b: Find this length
Side c: 50'
Angle A: unknown
Angle B: unknown
Angle C: 52 degrees
I am supposed to use the law of cosines to solve for side "b" and my teacher
says there is no mistake in the "givens" for the problem. I do not see how
this can be done using the law of cosines and i have not figured out how to solve for
angle B to use the law of cosines.

Hi Michael,

You can use the Law of Sines to find the measure of the angle A and hence deduce the measure of the angle B.


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