Recall that
[tex]\vec a\cdot\vec b=\|\vec a\|\|\vec b\|\cos\theta[/tex]
where [tex]\theta[/tex] is the angle between the vectors [tex]\vec a,\vec b[/tex] whose magnitudes are [tex]\|\vec a\|,\|\vec b\|[/tex], respectively.
We have
[tex]\langle6,4\rangle\cdot\langle7,5\rangle=\sqrt{6^2+4^2}\sqrt{7^2+5^2}\cos\theta[/tex]
[tex]\cos\theta=\dfrac{31}{\sqrt{962}}\implies\theta\approx88.2^\circ[/tex]
