A(1,-2,1),B(0,-2,4),C(3,-2,1),D(-3,4,1)
/AB/=√((0-1)²+(-2+2)²+(4-1)²)=√(1+0+9)=√10
/CD/=√((-3-3)²+(4+2)²+(1-1)²=√(36+36+0)=√72=6√2
→
AB=(0-1,-2+2,4-1)=(-1,0,3)
→
BC=(3-0,-2+2,1-4)=(3,0,-3)
→
CD=(-3-3,4+2,1-1)=(-6,6,0)
→
AD=(-3-1,4+2,1-1)=(-4,6,0)
→
AC=(3-1,-2+2,1-1)=(2,0,0)
→ →
CB=(0-3,-2+2,4-1)=(-3,0,3)=-BC