The law of cosines for ABC can be set up as 52 = 72 + 32 - 2 (7) (3) cos (B). What could be true about ABC? Law of cosines: a2 = b2 + c2 - 2bccos (A) a = 5 and c = 7 a = 3 and c = 3 b = 7 and c = 5 b = 5 and c = 3

The law of cosines is used for calculating one side of the triangle if the angle opposite to that side is given as well as the other sides. For this problem, we are given angle B. Therefore, the correct answer among the choices given is option 1 where a is equal to 5 and c is equal to 3.