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ChinaGurl
Two lines are perpendicular. If one line has a slope of 1/21 , what is the slope of the other line? A. -1/21 B. 1/21 C. 21 D. -21
Perpendicular lines have slopes that are negative reciprocals. That isa fancy mathematical way of saying that if you have the slope of one line and you want the slope of a perpendicular to that line, filp the fraction and change the sign.
1/21 Filp it: 21/1 = 21 Change sign: -21
Flip the sign and negate it. 1/21 becomes -1/21.Now flip. Becomes -21.