*Lenght (Magnitude) of Vector $$ \begin{aligned} \overrightarrow{V} &= (x,y) \\ |V| &= \sqrt{x^2 + y^2} \\ \overrightarrow{V} &= (3,4) \\ |V| &= \sqrt{3^2 + 4^2} =\sqrt{25} = 5\\ \end{aligned} $$ *Dot Product(Inner Product) $$ \begin{aligned} \A*B = AxBx + AyBy \ \end{aligned} $$