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Grade 8 math · L.2 · Angles and polygons

Alternate interior angles and parallel lines

Parallel lines cut by a transversal make equal angles (corresponding, alternate, vertical) and angles that add to 180° (straight line, co-interior).

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  1. Two parallel lines are cut by a transversal. One angle measures 82°. What is the measure of an angle that is its alternate interior angle?

    Answer: 82

  2. Two parallel lines are cut by a transversal. One angle measures 96°. What is the measure of an angle that is its alternate interior angle?

    Answer: 96

  3. Two parallel lines are cut by a transversal. One angle measures 77°. What is the measure of an angle that is its alternate interior angle?

    Answer: 77

Tip: Parallel lines cut by a transversal make equal angles (corresponding, alternate, vertical) and angles that add to 180° (straight line, co-interior).

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