U trokutu

su dane visine

,

,

, pri čemu je

Dokažite da je trokut

jednakostraničan.
%V0
U trokutu $ABC$ su dane visine $\overline{AA_1}$, $\overline{BB_1}$, $\overline{CC_1}$, pri čemu je $$\overrightarrow{AA_1} + \overrightarrow{BB_1} + \overrightarrow{CC_1} = \overrightarrow{0}\text{.}$$
Dokažite da je trokut $ABC$ jednakostraničan.