11. In the following years it continued to expand, with two perpendicular lines in place by the end of 1978. 12. The third method is based upon a larger number of measurements, but does not require the drawing of perpendicular lines . 13. The product of the slopes of perpendicular lines is " 1, assuming that both of the slopes are finite. 14. A perpendicular line drawn from each of these angles results in an overlapping 27 degree wedge claimed by both states. 15. The attack team will be giving 20 minutes to cross the perpendicular lines from the home-base to the back-end and return. 16. Josh knew from his class work that the algebraic formula for perpendicular lines involved the negative reciprocal of a certain number. 17. Four valves, one on each side of the blast, one on a perpendicular line and a final valve had to be closed. 18. Horizontal and perpendicular lines are marked off on this face with cord, the interval suited to the size of the root system. 19. Then we erect a perpendicular line to the diameter in " D " that intersects the half circle in " C ". 20. Another method : Find the center, and hence the radius, by constructing tangent lines at both ends and constructing perpendicular lines to those.
