Calculate the angle between two vectors using ArcCos or Diamond Angle

$\vec{A}\times\vec{B} = \|\vec{A}\|\times\|\vec{B}\|\times\sin\theta\times\widehat{\vec{N}}$
Where $\vec{N}$ is perpendicular to the $\vec{A}$, $\vec{B}$ plane.

$\vec{A}\cdot\vec{B} = \|\vec{A}\|\times\|\vec{B}\|\times\cos\theta$
$\vec{A}[x_{_1}, y_{_1}]\cdot …$