What do you notice about the slopes of your two lines?
What are the slopes of your two lines?
What happens to the slopes as the lines become steeper?
What happens when the lines are parallel and vertical?
Directions for #5
How many of the lines now have a positive slope?
How many of the lines now have a negative slope?
What do you get when you multiply the two slopes together?
Rearrange your lines so that one line is vertical and one line is horizontal. What do you get when you multiply the slopes of these two lines together?
Rearrange your line so that they are once again parallel. What do you notice about their slopes? What will always be true about the slopes of parallel lines?
Slopes of perpendicular lines can multiply to