Question

If A(x1, y1), B(x2, y2), C(x3, y3), and D(x4, y4) form two line segments, AB and CD , which of these conditions needs to be met to prove that AB is perpendicular to CD?
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Answer 1

@Vocaloid

Answer 2

product of the slopes should be -1

Answer 3

I know, but like... It's not one of the options

Answer 4

OH WAIT YES IT IS

Answer 5

good

Answer 6

third one?

Answer 7

Sorry, I read that it wrong and didn't see the negative symbol