![](thumbFetcher.php?id=55&size=thumb) | Parallel lines never intersect and have the same slope. | |
| ![](thumbFetcher.php?id=58&size=thumb) | Perpendicular lines intersect at 90 degrees. One line's slope is the opposite reciprocal of the other's. | |
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| ![](thumbFetcher.php?id=289&size=thumb) | Two coplanar lines that intersect. | |
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![](thumbFetcher.php?id=290&size=thumb) | Dotted lines represent hidden portions of the plane. | |
| ![](thumbFetcher.php?id=291&size=thumb) | Two planes intersect in a line. | |
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![](thumbFetcher.php?id=292&size=thumb) | Any line that contains A and is on the plane is perpendicular to line AB. | |
| ![](thumbFetcher.php?id=293&size=thumb) | Line intersecting a plane at point A. The dotted portion of the line is occluded by the visible part of the plane. | |
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![](thumbFetcher.php?id=294&size=thumb) | 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. | |
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