|vector{AC}|=sqrt((-2)^2+2^2+1^2))=3
vector{AB}=((3-2);(-1-0);(2-1))=(1;-1;1)
|vector{AB}|=sqrt(1^2+(-1)^2+1^2)=sqrt(3)
vector{AC}*vector{AB}=(-2)*1+2*(-1)+1*1=-3.
cos∠A=vector{AC}*vector{AB}/|vector{AC}|*|vector{AB}|=-3/3sqrt(3)=-1/sqrt(3)
sin^2∠A=1-cos^2∠A=1-(-1/sqrt(3))=1-(1/3)=2/3
sin∠A=sqrt(2/3)
h=AB*sin∠A=sqrt(3)*sqrt(2/3)=sqrt(2)
О т в е т. sqrt(2)