Question 106084
1. the side through the points ({{{2}}},{{{3}}}) and ({{{11}}},{{{6}}})

Find a slope {{{a[1]}}}:


{{{a[1]}}} = ({{{y[2]}}} –{{{y[1]}}})/({{{x[2]}}} – {{{x[1]}}})

{{{a[1] = (6-3)/(11-2)}}}

{{{a[1]= 3/9}}}

{{{a[1] = 1/3}}}



2.
the side through the points ({{{2}}},{{{3}}}) and ({{{-3}}},{{{18}}})

Find a slope {{{a[2]}}}:


{{{a[2]}}} = ({{{y[2]}}} –{{{y[1]}}})/({{{x[2]}}} – {{{x[1]}}})

{{{a[2] = (18-3)/(-3-2)}}}

{{{a[2]= 15/(-5)}}}

{{{a[2] = -3}}}


If the product of slopes is equal to {{{-1}}}, lines are {{{perpendicular}}}.

We have {{{a[1] =1/3}}} and {{{a[2] = -3}}},

so

{{{a[1]*a[2] = (1/3)*(-3)}}}

{{{a[1]*a[2] = -1}}}   ............. => your lines are {{{perpendicular}}}