Geometry

Question Analysis

The problem is about using the Law of Cosines to find the measure of  in , given the lengths of all three sides (, , ).

 

Key Concept Explanation

The Law of Cosines states that for a triangle with sides , ,  and the angle  opposite side , . Rearranging this formula to find an angle gives . For , to find , we use , since we know the side lengths and want the angle opposite side .

 

Step - by - Step Solution

1. Identify the values: Let , , .

2. Calculate:

Compute the squares:

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