Perpendicularity

• Linear Pair Perpendicular Theorem


  When two straight lines intersects at a point and forms a linear pair of equal angles, then they are perpendicular.
• Perpendicular Lines Theorem


  If two lines are perpendicular, then they intersect to form four right angles. If one angle is a right angle, then the other three are also right angles.
• Perpendicular Transversal Theorem


  In a plane, if a line is parallel to another line and is perpendicular, then the other line is also perpendicular.