3-7 Perpendicular Lines
Lines that intersect at an angle of 90 degrees are perpendicular lines. For example, let’s say that we have the and the line ABline CD A B CD Now, if the lines intersect at an angle of 90 o, then AB CD.
Definition of Perpendicular Lines Perpendicular lines are lines that intersect to form a right angle. m n Symbols: m n
m n
Theorem 3-8 If two lines are perpendicular, a b Symbols: a b then they form 4 right angles
R In the figure, P O M N OP MNNP QS. and Q S Determine whether each of the following is true or false. 1 2 False. True. Since OP MN, are vertical angles, and vertical angles are congruent. 3 4 QR PR False. True.If two lines are perpendicular, then they form 4 right angles.