The correct answer is
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°.
To solve for
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, you can start by finding the measures of the triangle's interior angles. Knowing that a straight line measures
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°, you can subtract the given values from
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° to find the measures of the respective supplementary interior angles. That would give you
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°
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and
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°
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.
Now, knowing that the measure of all the interior angles of a triangle is also
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°, you can add the two interior angles you know
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and subtract those from
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°. Doing so would give you the measure of the missing third angle, which is
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°.
Finally, because angle
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is the supplementary angle of the missing angle from the previous step, simply subtract that angle's measure from
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° to find
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°, which is
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or
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°.