SOLUTION: How can I determine if two lines are perendicular?

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Question 451720: How can I determine if two lines are perendicular?
Found 2 solutions by ewatrrr, richard1234:
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 

Hi

How can I determine if two lines are perendicular? 

I. Put both lines in the slope-intercept form

II.  compare their slopes

III. If the slopes ae negative reciprcals of one another: for ex:  -2/3 and 3/2

THEN these lines are perpendicular

Answer by richard1234(7193) About Me  (Show Source):
You can put this solution on YOUR website!
Show that the angle in between these lines is 90 degrees. Or show that the slopes are negative reciprocals of each other. Or if your lines are vectors, show that the dot product is equal to 0. Quite a few ways to prove this.