In a triangle angle A measure 42 degrees, side a is 6 in and side c is 9 units. What are the possible measurements for angle B?

Answer 1

Hi Matthew B.,

Use the law of cosines for a² = b² + c² - 2(b)(c)cos(A).

Using what was given: 6² = b² + 9² - 2(b)(9)cos(42^o).

With some algebra you will get, 0 = b² -13.38b + 45, and if you try solving for b you will see there are no real solutions. So there are no possible real solutions for the measurement of angle B.

I hope this helps, thanks.