$\"\"$

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Observe the right triangle figure, the sides are $\"\"$ .

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$\"\"$ (Write alternative form of cosines law)

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$\"\"$ (Substitute $\"\"$ )

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$\"\"$ (Apply property of exponents)

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$\"\"$ (Simplify)

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$\"\"$ (Multiply each side by $\"\"$ )

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$\"\"$ (Use calculator) $\"\"$

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$\"\"$ (Write reciprocal form of sines law)

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$\"\"$ (Substitute $\"\"$ )

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$\"\"$ (Multiply each side by 3)

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$\"\"$ (Use calculator)

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$\"\"$ (Multiply each side by $\"\"$ )

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$\"\"$ (Use calculator) $\"\"$

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In a triangle, the total of three angles is $\"\"$ .

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$\"\"$ (Write total of three angles)

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$\"\"$ (Substitute $\"\"$ )

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$\"\"$ (Subtract $\"\"$ from each side) $\"\"$

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The angles are $\"\"$ .