The smaller two sides of an obtuse triangle are known to be 4.0 m and 10.6 m. The angle that is opposite 10.6 is 14 degrees.

Question

A) Calculate the obtuse angle in the triangle, to the nearest tenth of a degree. Show all your work and make sure you include the equation.

Answer 1

In ∆ABC, let A=14°, a=10.6, c=4
We want to find B.
sinC/c = sinA/a, so sinC/4 = sin14°/10.6
sinC = 0.09129
C = 5.23°
So B = 180-(14-5.23) = 160.76°