<PRE><B>Question 1136913</B>
A({{{1}}},{{{-2}}})  B({{{4}}},{{{2}}})  C({{{6}}},{{{2}}})  D({{{3}}},{{{-2}}})

use distance formula to find out if distances {{{AB}}}, {{{CD}}},{{{AD}}}, and {{{BC}}} are same; if yes than this quadrilateral with the given vertices is a square

{{{AB}}}

*[invoke formula_distance 1, -2, 4, 2]

{{{CD}}}

*[invoke formula_distance 6, 2, 3, -2]


{{{AD}}}

*[invoke formula_distance 1, -2, 3, -2]

{{{BC}}}

*[invoke formula_distance 6, 2, 4, 2]


this quadrilateral with the given vertices is {{{not}}} a square


{{{drawing( 600, 600, -10, 10, -10, 10,
circle(1,-2,.12),locate(1,-2,A(1,-2)),
circle(4,2,.12),locate(4,2,B(4,2)),
circle(6,2,.12),locate(6,2,C(6,2)),
circle(3,-2,.12),locate(3,-2,D(3,-2)),
line(1,-2,4,2),line(1,-2,3,-2),line(6,2,3,-2),line(6,2,4,2),
 graph( 600, 600, -10, 10, -10, 10, 0)) }}}



</PRE>