3.4. Properties of Perpendicular Lines http://www.ck12.org
3.4 Properties of Perpendicular Lines
Learning Objectives
- Understand the properties of perpendicular lines.
- Explore problems with parallel lines and a perpendicular transversal.
- Solve problems involving complementary adjacent angles.
Review Queue
Determine if the following statements are true or false. If they are true, write the converse. If they are false, find a
counter example.
- Perpendicular lines form four right angles.
- A right angle is greater than or equal to 90◦.
Find the slope between the two given points.
- (-3, 4) and (-3, 1)
- (6, 7) and (-5, 7)
Know What?There are several examples of slope in nature. Below are pictures of Half Dome in Yosemite National
Park and the horizon over the Pacific Ocean. These are examples of horizontal and vertical lines in real life. Can
you determine the slope of these lines?
Congruent Linear Pairs
Recall that a linear pair is a pair of adjacent angles whose outer sides form a straight line. The Linear Pair Postulate
says that the angles in a linear pair are supplementary. What happens when the angles in a linear pair are congruent?