A triangle has sides A, B, and C. Sides A and B are of lengths #5# and #6#, respectively, and the angle between A and B is #(5pi)/12 #. What is the length of side C?
c = 6.74 ( 2 decimal places )
I recommend that you draw a sketch of the triangle where you will see that we are given 2 sides and the included angle ie. the angle between the 2 given sides.
For this condition to find the third side use the cosine rule
substitute these values into the cosine rule
At this stage remember to take the square root to get c.