Geometry

Question Analysis

The question asks us to pick the right formula to find side in △ABC, testing our understanding of when to use the Law of Sines or Law of Cosines given two sides and a non - opposite angle.

Key Concept Explanation

Law of Sines: , used when we know an angle - opposite side pair and another side or angle.

Law of Cosines: , applied when we know two sides and the included angle (SAS) or all three sides (SSS).

Step-by-Step Solution

1. Since we know sides , and the included angle , we use the Law of Cosines formula

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