已知点A(1,0) B(5,-2)C(8,4)D(4,-6)求证四边形ABCD是矩形

|AB|=√(5-1)^2+(0+2)^2=2√5|BC|=√(8-5)^2+(4+2)^2=3√5|AD|=√(4-1)^2+(0+6)^2=3√5|AC|=√(8-1)^2+(4-0)^2=√65|CD|=√(8-5)^2+(4+2)^2=3√5因为AB=CD,AD=BC所以四边形为平行四边形因为AB^2+BC^2=65 =AC^2所以...