Algebra 1 : How to find the slope of perpendicular lines

Study concepts, example questions & explanations for Algebra 1

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Example Questions

Example Question #61 : Perpendicular Lines

What must be the slope of a line that is perpendicular to ?

Possible Answers:

Correct answer:

Explanation:

The equation  is a vertical line, which means there is a zero denominator for the run.   The slope is undefined for vertical lines.

The perpendicular line will intersect this equation with a ninety degree angle, which means that the line is rotated ninety degrees, and will form a horizontal line.  Recall that the slopes of horizontal lines are zero.

The slope of a line perpendicular to  is zero.

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