Law of Cosines Find Side BC in Triangle ABC with AB=30, AC=25, Angle A=32 Degrees

Published on November 3, 2026

Trigonometry

Find the length of side BC in a triangle where two sides are 30 and 25 and the included angle A is 32 degrees, using the Law of Cosines: BC squared equals AB squared plus AC squared minus 2 times AB times AC times cos A, giving BC of approximately 15.90.

Question

Answer

Step 1: Apply the Law of Cosines at vertex A

Step 2: Substitute the values

Using

Step 3: Take the square root

Answer:

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