1. 3.1 Identify Pairs of Lines and Angles

2. Parallel Lines Coplanar Do not intersect
Triangles, like those above in red, indicate that 2 lines are parallel. D B
Coplanar
Do not intersect
Segments and rays are parallel if they lie on parallel lines. C

3. Parallel planes if they never intersect

4. B C D A F G E H

5. B C A D F G E H

6. Skew Lines: Do not intersect, but do not lie in the same plane.G C B

7. A D E H G C B F

8. B C D A F G E H

9. #13: Parallel Postulate
If there is a line and a point not on the line,

10. #13: Parallel Postulate
If there is a line and a point not on the line, then there is exactly one line through the point and parallel to the line

11. #14: Perpendicular Postulate
If there is a line and a point not on the line, then there is exactly one line through the point and perpendicular to the line

12. Corresponding Angles Same side of transversal Corresponding position
Transversal; intersects 2 or more coplanar lines
Corresponding Angles Same side of transversal Corresponding position

14. Alternate Exterior Angles “Alternate”  opposite sides of transversal “Exterior”  outside of the two lines

15. Alternate Interior Angles “Alternate”  opposite sides of transversal “Interior”  inside of the two lines

16. Consecutive Interior Angles “Consecutive”  “together”; same side of the transversal “Interior”  inside of the two lines

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