Texas HS Geometry Question of the Day

$LM \perp MN$ because $m_{LM}\cdot m_{MN}=-1$.

Only one pair of opposite sides is parallel: $LM \parallel NO$ but $MN \nparallel OL$.

The diagonals bisect each other: $M_{LN}=(\tfrac{0+8}{2},\tfrac{1+(-1)}{2})=(4,0)$ and $M_{MO}=(\tfrac{6+2}{2},\tfrac{3+(-3)}{2})=(4,0)$, so $LMNO$ is a parallelogram.

All four sides are congruent.