## Monday, July 16, 2007

### Geometry Chapter 3.1 Lines and angles

Geometry Chapter 3.1 Lines and Angles:

I) Vocabulary:
A) Parallel Lines (ll): two lines that are coplanar and do not intersect.
B) Skew lines: two lines that doe not intersect and are not coplanar.
C) Parallel Planes: Planes that do not intersect.
II) Postulates:
A) If there is a line and a point not on the line, then there is exactly one line through the point parallel to the given line.
B) If there is a line and a point not on the line, then there is exactly one line through the point perpendicular to the given line.
III) Identifying Angels formed by transversals:
A) Transversal: is a line that intersects two or more coplanar lines at different points.
B) Corresponding angles: if you have two lines that are intersected by a transversal, the the two angles that occupy the same position - (eg. to the left of the transversal and on top of the two lines)
C) Alternate interior angles: if you have two lines that are intersected by a transversal, then the two angles that lie between the two lines and on opposite sides of the transversal.
D) Alternate exterior angles: if you have two lines that are intersected by a transversal, then the two angles that lie outside the two lines on opposite sides of the transversal.
E) Consecutive Interior Angles: two angles if they lie between the two lines on the same side of the transversal. Also known as same side interior angles.