| A | B |
|---|
| Parallel lines | lines in the same plane that do not intersect |
| skew lines | lines not in the same plane that do not intersect |
| transversal | a line that intersects two or more lines in a plane at different points |
| Corresponding angle postulate | If two parallel lines are cut by a transversal then corresponding angles are congruent. |
| Alternate interior angles theorem | If two parallel lines are cut by a transversal then alternate interior angles are congruent |
| alternate exterior angles theorem | If two parallel lines are cut by a transversal then alternate exterior angles are cogruent |
| consecutive interior angle theorem | If two parallel lines are cut by a transversal then consecutive interior angles are supplementary |
| consecutive exterior angle theorem | If two parallel lines are cut by a transversal then consecutive exterior angles are supplementary |
| perpendicular transversal theorem | In a plane, if a line i perpendicular to one of two parallel lies then it is perpendicular to the other. |
| Two skew lines are parallel (S/A/N) | Never |
| Two parallel lines are coplanar (S/A/N) | Always |
| A line in the plane of the ceiling and a line in the plane of the floor are parallel (S/A/N) | Sometimes |
| Two lines in the plane of the floor are skew (S/A/N) | Never |
| Parallel postulate | If there is a line and a point not on that line, then there exists exactly one line through the point that is parallel to the given line |
| Name the five ways to prove that lines are parallel | If alternate interior angles are congruent, if alternate exterior angles are congruent, if consec. interior angles are supp.,if consec. ext angles are supp, or if corresponding angles are congruent. |
| In a plane, if two lines are perpendicular to the same line then... | the lines are parallel |
| Slope of a line | the ratio of the vertical and horizontal change between two point on a line (subt. the y's over subt. the x's) |
| If two lines are parallel then what relationship does their slopes have? | Their slopes are equal |
| If two lines are perpendicular then what relationship exists with their slopes? | Their slopes are negative reciprocals of each other |
| The distance from a line to a point not on that line is... | the length of the segmen perpendicular to the line from the point |
| The distance between two parallel lines is... | the distance between one of the lines and any point on the other line |
| Alternate interior angles are congruent (S/A/N) | Sometimes (only when the lines are parallel) |
| Two lines parallel to the same plane are parallel to each other (S/A/N) | Sometimes (They could be skew) |
