The given problem presents one with the following information:
Triangle ABC
Side (b) has a measure of (13.5)
Side (c) has a measure of (8.9)
Angle (A) has a measure of (29)
To solve this problem, one can use the law of cosines. The law of cosines is a property that can apply to any triangle. This property comes in the form of a formula, which is as follows:
Where (a), (b), and (c) are sides of the triangle, and (<A) is the angle opposite the side (a).
Substitute the given information into the formula and solve for the unknown side (a):