# What is the angle between <-7,4,-7 >  and < 4,3,0 >?

$\theta = {107.44}^{\circ}$
cos theta = (<-7,4,-7>*<4,3,0>)/(sqrt((-7)^2+4^2+(-7)^2) sqrt(4^2+3^2+0^2)
$\cos \theta = \frac{- 7 \left(4\right) + 4 \left(3\right) + \left(- 7\right) \left(0\right)}{\sqrt{114} \sqrt{25}}$
$\theta = {\cos}^{-} 1 \left(- \frac{16}{\sqrt{2850}}\right) = {107.44}^{\circ}$