In topic 3.4.2 we will be talking about how slope affects parallel and perpendicular lines. As you recall, parallel lines are equally spaced and will never intersect and perpendicular lines are two lines that intersect at 90 degrees. So how does slope affect these types of lines? What makes their slopes unique compared to just any two lines graphed on the same coordinate plane?
Now lets look at two perpendicular lines. We know they are perpendicular because they form a right angle when they intersect. But what if you couldn't tell for sure that they were intersecting at 90 degrees? Again, we can use their slopes to prove whether they are perpendicular or not. Find the slope of each line. What do you notice? How do these two lines slopes compare? |