In triangle ABC The lengths of the sides AB and BC are known. To find the side AC

In triangle ABC The lengths of the sides AB and BC are known. To find the side AC, you need to know the value of: a) angle A b) angle B c) angle C

To determine the side of the AC, it is necessary and sufficient to know the angle between the given sides: AB and BC, or the angle opposite to the AC side itself, that is, this angle <C, since AC is determined by the following formula:

(AC) ^ 2 = (AB) ^ 2 + (BC) ^ 2 – 2 * AB * BC * cos (<B).

Answer: b) angle B.