1. Lesson 3.1 Lines and Angles

2. Parallel Lines Two lines that are coplanar and do not intersect
Symbol: II

3. Skew Lines
Lines do not intersect and are not coplanar

4. Parallel planes Two planes that do not intersect Example 1
Give lines II to XY
Give II planes
Give lines skew to XY

5. Parallel Postulate
If there is a line and a point not on the line then there is exactly one line through the point II to the given line.

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

7. Transversal
A line that intersects two or more coplanar lines at different points.
transversal

8. Angles formed by transversal
Corresponding Angles: occupy corresponding positions.
Alternate Exterior Angles: lie outside the 2 lines on opposite sides of the transversal.

9. Angles formed by transversal
Alternate Interior Angles: Lie between the 2 lines on opposite sides of the transversal.
Consecutive Interior Angles: (same side) lie between the 2 lines on the same side of the transversal.

10. Angle Relationships: Name a pair of angles
Corresponding
Ex. 1 & 5
Alternate Exterior
Ex. 1 & 8
Alternate Interior
Ex. 4 & 5
Consecutive Interior
Ex. 3 & 5 1 2 3 4 5 6 7 8