1. In calculus terms, if y and k are two perpendicular lines : 2. Draw perpendicular lines connecting A point and B Point to the Occlusal Plane 3. 3. The angle between the perpendicular line and the femoral shaft line is the angle. 4. All of them, except the pentagon, have bilateral ( reflection ) symmetry through two perpendicular lines . 5. Let L _ 1 and L _ 2 be any two mutually perpendicular lines through H. 6. Henceforth the organization would be known as the Post-Columbian Muted Gray Bisecting Perpendicular Lines , or PCMGBPL. 7. Given a line, the negative reciprocal of its slope is the slope of a perpendicular line . 8. With respect to perpendicular lines , they remain perpendicular when the plane is subjected to ordinary rotation. 9. To mark the notches, first draw perpendicular lines across both edges at four inches from each end. 10. Anyway, the product of the slopes of two perpendicular lines is-1, ( This site explains why reasonably well ).