## Elementary Geometry for College Students (7th Edition)

$\frac{a}{b}$
As we know that the perpendicular lines is equal to m1m2=-1 we know m=$\frac{b-0}{0-a}$ = $\frac{-b}{a}$ therefore $\frac{-b}{a}$*m2 = -1 m2=$\frac{a}{b}$