Angle θ between two vectors is given by, [tex] \theta =cos^{-1}( \frac{u
\cdot v}{|u||v|} )[/tex]; where [tex]u \cdot
v=8(9)+(7)(7)=72+49=121[/tex]; [tex]|u|= \sqrt{ 8^{2} + 7^{2} } =
\sqrt{64+49} = \sqrt{113} [/tex] and [tex]|v|=\sqrt{ 9^{2} + 7^{2} } =
\sqrt{81+49} = \sqrt{130}[/tex].
Therefore, [tex]\theta =cos^{-1}( \frac{121}{ \sqrt{113} \times \sqrt{130} } )=cos^{-1}0.9983=3.3^o[/tex]
