WEBVTT

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Here is the problem: Solve the triangle with sides a equals 5, b equals 12, c equals 13.

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Side a is opposite angle A, b opposite B and c opposite C. This is the SSS case.

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Each angle from the law of cosines.

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Area and perimeter.

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So the answer is a equals 5, b equals 12, c equals 13; A equals 22.61986495°, B equals 67.38013505°, C equals 90°; area equals 30, perimeter equals 30.

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Three measurements including a side normally fix a triangle. Two sides with a non-included angle (SSA) can give zero, one or two triangles.

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Triangle 1: angles sum to 180°; a/sin A equals 13 equals c/sin C equals 13.