Geometry Parallel Lines & Transversals 1 — Questions and Answers
Question 1: When two parallel lines are cut by a transversal, alternate interior angles are _____.
- supplementary
- equal (Correct answer)
- complementary
- vertical
Correct answer: equal
Alternate interior angles are congruent (equal) when the lines cut by the transversal are parallel.
Question 2: Co-interior angles (same-side interior angles) formed by two parallel lines and a transversal sum to _____.
- 90°
- 270°
- 180° (Correct answer)
- 360°
Correct answer: 180°
Co-interior (consecutive interior) angles are supplementary, always summing to 180° when the lines are parallel.
Question 3: Corresponding angles formed when a transversal cuts two parallel lines are _____.
- supplementary
- complementary
- vertical
- congruent (Correct answer)
Correct answer: congruent
Corresponding angles occupy the same relative position at each intersection and are equal when lines are parallel.
Question 4: When a transversal intersects two parallel lines, how many pairs of corresponding angles are formed?
- 2
- 8
- 6
- 4 (Correct answer)
Correct answer: 4
The transversal creates 4 angles at each of the 2 intersections (8 angles total), forming exactly 4 pairs of corresponding angles.
Question 5: If one co-interior angle measures 115°, what is the other co-interior angle when the lines are parallel?
- 115°
- 75°
- 55°
- 65° (Correct answer)
Correct answer: 65°
Co-interior angles sum to 180°, so the other angle is 180° − 115° = 65°.
Question 6: Alternate exterior angles are located _____.
- between the two parallel lines on the same side of the transversal
- between the two parallel lines on opposite sides of the transversal
- outside the parallel lines on the same side of the transversal
- outside the parallel lines on opposite sides of the transversal (Correct answer)
Correct answer: outside the parallel lines on opposite sides of the transversal
Alternate exterior angles are on opposite sides of the transversal and exterior (outside) to the two parallel lines.
Question 7: If a transversal cuts two lines and the alternate interior angles are NOT equal, then the two lines are _____.
- parallel
- perpendicular
- congruent
- not parallel (Correct answer)
Correct answer: not parallel
Alternate interior angles are equal only when the lines are parallel; unequal alternate interior angles indicate the lines are not parallel.
Geometry Parallel Lines & Transversals 1
When two parallel lines are cut by a transversal, alternate interior angles are _____.