Law of cosines: two sides and the angle between them

An example figure from the Triangle Generator.

Triangle ABC with AB labeled 8 m, CA labeled 11 m, the 40° angle between them at A, and the third side BC labeled x — A triangle ABC drawn to scale with two sides and the angle between them given: AB is 8 m, CA is 11 m and ∠A is 40°, marked with an arc. The third side, BC, is labeled x. There is no right angle, so students use the law of cosines.

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Answer key

BC = 7.1 m
∠B = 93.5°
∠C = 46.5°

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