[tex]\displaystyle\\
\overrightarrow{AB}+\overrightarrow{BC}=\overrightarrow{AC}~~~\text{Conform relatiei lui {\it Chasles}}\\\\
\Longrightarrow~~~\overrightarrow{AC}=\overrightarrow{AB}+\overrightarrow{BC}=2i+2j ~~+~~2i+j = \boxed{4i+3j}\\\\
\text{Lungimea lui }\overrightarrow{AC} = \Big|\overrightarrow{AC}\Big| =\Big|4i+3j\Big|\\\\
\Big|4i+3j\Big|=\sqrt{4^2 + 3^2}=\sqrt{16 + 9}= \sqrt{25}=\boxed{\bf 5}[/tex]
