100 likes | 272 Views
Lesson 3.1 Lines and Angles. Parallel Lines. Two lines that are coplanar and do not intersect Symbol: II. Skew Lines. Lines do not intersect and are not coplanar. Parallel planes. Two planes that do not intersect Example 1 Give lines II to XY Give II planes Give lines skew to XY.
E N D
Parallel Lines • Two lines that are coplanar and do not intersect • Symbol: II
Skew Lines • Lines do not intersect and are not coplanar
Parallel planes • Two planes that do not intersect • Example 1 • Give lines II to XY • Give II planes • Give lines skew to XY
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.
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.
Transversal • A line that intersects two or more coplanar lines at different points. transversal
Angles formed by transversal • Corresponding Angles: occupy corresponding positions. • Alternate Exterior Angles: lie outside the 2 lines on opposite sides of the transversal.
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.
1 2 3 4 5 6 8 7 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