How do you solve the triangle ABC given a=55, b=25, c=72?
"Solve a triangle" means find all the missing information - in this case, the size of each angle.
The lengths of 3 sides are given. We must use the Cosine Rule.
Find the biggest angle first - if it is an obtuse angle, the Cos rule will indicate this, but the Sin Rule will not,
Angle C is the biggest angle because it is opposite the longest side.
Now use the SIn Rule.
We have 2 angles, use the angle sum of a triangle to find