Unit 5 - Lesson 1

Perpendicular Lines

What makes 2 lines perpendicular?

Two lines are perpendicular is their slopes are opposite reciprocals!
Remember reciprocal means the fraction has flipped over (top and bottom switch)

How do you write the equation of a line perpendicular to a given line passing through a given point?

Step 1: Find the SLOPE of the given line.


slope, this will be the slope (m) 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.

Find the equation of the line perpendicular to y = -1/3x + 4 through the point (6, -2).

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