Question 1173739
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Hi,
{{{drawing(300,300,   -15,15,-15,15,  
 grid(1),
circle(1,-2,0.4),
circle(13,4,0.4),
circle(6,8,0.4),
circle(-2,4,0.4),
line(-2,4,6,8),
line(6,8,13,4),
line(13,4,1,-2),
line(-2,4,1,-2),
locate(.5,-2.5,A),
locate(13.5,4,B),
locate(6.5,9.5,C),
locate(-2.5,6, D),
graph( 300, 300, -15,15,-15,15,0 ))}}}
m ={{{(y[1] - y[2])/(x[1] - x[2] )}}}
A(1,-2)                                            C(6,8)          
B(13,4),  m = -6/-12 = 1/2 *            D(-2,4),  m = 4/8 = 1/2 *
AB is parallel to CD as the slopes of these two sides segments are equal.
Two sides of the quadrilateral are parallel: it is a trapezoid

distance  A(1,-2) to  D(-2,4) is {{{sqrt(3^2 + (-6)^2)}}} = √45     D = {{{ sqrt ( (x[1]-x[2])^2+ (y[1]-y[2])^2 ) }}}
distance  B(13,4) to  C(6,8) is {{{sqrt(7^2 + (-4)^2)}}} = √65  
 AB and BC are NOT the same length- is not an isosceles trapezoid.