Bluebook SAT Test Lines, Angles, and Triangles 1 — Questions and Answers
Question 1: Two parallel lines are cut by a transversal. One co-interior (same-side interior) angle is 65°. What is the other co-interior angle?
- 65°
- 115° (Correct answer)
- 125°
- 180°
Correct answer: 115°
Co-interior angles are supplementary: 180° − 65° = 115°.
Question 2: In a triangle, two angles measure 47° and 83°. What is the third angle?
- 40°
- 50° (Correct answer)
- 60°
- 130°
Correct answer: 50°
Third angle = 180° − 47° − 83° = 50°.
Question 3: Two lines intersect and one angle measures 72°. What is the vertically opposite angle?
- 18°
- 72° (Correct answer)
- 108°
- 144°
Correct answer: 72°
Vertical angles are equal; the opposite angle is 72°.
Question 4: A transversal crosses two parallel lines. One corresponding angle is 110°. What is the other corresponding angle?
- 70°
- 80°
- 110° (Correct answer)
- 140°
Correct answer: 110°
Corresponding angles formed by parallel lines are equal: 110°.
Question 5: An isosceles triangle has a vertex angle of 40°. What is each base angle?
- 40°
- 60°
- 70° (Correct answer)
- 140°
Correct answer: 70°
2x + 40 = 180 → x = 70°.
Question 6: The exterior angle of a triangle is 120°. One non-adjacent interior angle is 45°. What is the other non-adjacent interior angle?
- 45°
- 60°
- 75° (Correct answer)
- 90°
Correct answer: 75°
45° + x = 120° → x = 75°.
Question 7: Two supplementary angles are in the ratio 1:3. What is the smaller angle?
- 30°
- 45° (Correct answer)
- 60°
- 90°
Correct answer: 45°
x + 3x = 180° → x = 45°.
Bluebook SAT Test Lines, Angles, and Triangles 1
Two parallel lines are cut by a transversal.
One co-interior (same-side interior) angle is 65°.
What is the other co-interior angle?