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Lines

by kanha81 » Wed Jun 24, 2009 10:19 am
Line l is defined by the equation y – 5x = 4 and line w is defined by the equation 10y + 2x + 20 = 0. If line k does not intersect line l, what is the degree measure of the angle formed by line k and line w? (Assume that all lines lie in one coordinate plane.)

A) 0

B) 30

C) 60

D) 90

E) It cannot be determined from the information given
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by SanjeevK » Wed Jun 24, 2009 10:44 am
IMO [spoiler]D:[/spoiler]
Line l: y – 5x = 4. Slope of this line is 5. Let's say m1 = 5.
Line w: 10y + 2x + 20 = 0 Slope of this line is say m2. m2 = -1/5.

Since m1xm2 = -1, we can say that line l is perpendicular to line w.
Since line k does not intersect line l, it means that line l is parallel to line k. Hence the angle between line k and line w is 90 degress.

Hope this helps.
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