In[]:=
origin={0,0,0};​​v1={.7,.4,.5};​​v2={0,0,1};​​VectorAngle[v1,v2]
Out[]=
1.01568
In[]:=
Graphics3D[{Red,Arrow[{origin,v1}],​​Black,Arrow[{origin,v2}]},Axes->True,Boxed->True]
Out[]=