Intersect to form a right angle (90 degress)!
Perpendicular lines can be found all around you!
What do we know about the slopes of perpendicular lines?
- They are opposite reciprocals!
- Remember: Flip it & change the sign!
Let's try an example!
Write the equation of the line perpendicular to the line below passing through the point (0, 4).
Step 1: Find the slope of the given line.
Step 2: Find the opposite reciprocal, this will be the slope for Step 3 & 4.
Step 3: Substitute the slope of the given line, and the x- & y- values of the given point into the equation y = mx + b, and solve for b.
Step 4: Substitute m & b into y = mx + b.
Let's look at another example!
Write the equation of the line perpendicular to y = (-1/2)x - 5 passing through the point (-4, 6).