we have that
\(A(0, 0)\\B(e, f)\\ C(0, e)\\D(f, 0)\)
we know that
If two lines are parallel
then
their slopes are equals
and
if two lines are perpendicular
then
the product of their slopes is equal to \(-1\)
step 1
find the slope of the line segment AB
\(m=\frac{(y2-y1)}{(x2-x1)}\)
\(mAB=\frac{(f-0)}{(e-0)}\)
\(mAB=\frac{(f)}{(e)}\)
step 2
find the slope of the line segment CD
\(m=\frac{(y2-y1)}{(x2-x1)}\)
\(mCD=\frac{(0-e)}{(f-0)}\)
\(mCD=\frac{(-e)}{(f)}\)
\(mAB*mCD=(\frac{f}{e} )*(\frac{-e}{f} )\\ =-1\)
therefore
the answer is
Line segments AB and CD are perpendicular
