Based on slope, how do you know when two lines are perpendicular? A. The slope of one line must be equal to reciprocal of the other for the two to be perpendicular. B. The slope of one line must be the negative reciprocal of the other for the two to be perpendicular. C. If the slopes of the 2 lines are equal, then they are perpendicular. D. The slope of one line must be the negative of the other slope for the two to be perpendicular.

B

Step-by-step explanation:

Perpendicular lines have negative reciprocal slopes. This means they have opposite signs (negative) and their numerators and denominators are switched ( reciprocal).

For example, these slopes are perpendicular:

3/2 and -2/3

(3/2--negate--> -3/2---> reciprocal--> -2/3)

Therefore, the answer is B.  The slope of one line must be the negative reciprocal of the other for the two to be perpendicular.

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