Answer
$76.87^{\circ}$
Work Step by Step
We know that the angle between two vectors is:
$\theta =\cos^{-1} [ \dfrac{u \cdot v}{||u|| \space ||v|| }]$
Therefore, $||u||=\sqrt{2^2+(-3)^2}=\sqrt{13}$ and $||v||=\sqrt{8^2+3^2}=\sqrt {73}$
$\theta =\cos^{-1} [ \dfrac{(2)(8)+(-3)(3)}{\sqrt {13}\sqrt {73}}]=\cos^{-1}[\dfrac{7 \sqrt{949}}{949}]$
So, $\theta =76.87^{\circ}$
