 | Parallel lines never intersect and have the same slope. | | |
|  | Perpendicular lines intersect at 90 degrees. One line's slope is the opposite reciprocal of the other's. | | |
|
|  | Two coplanar lines that intersect. | | |
|
 | Dotted lines represent hidden portions of the plane. | | |
|  | Two planes intersect in a line. | | |
|
 | Any line that contains A and is on the plane is perpendicular to line AB. | | |
|  | Line intersecting a plane at point A. The dotted portion of the line is occluded by the visible part of the plane. | | |
|
 | Angles formed by two lines cut by a transversal. The lines do not appear parallel in this diagram, but you are free to constrain them if needed. | | |
|
