[tex]\it \Delta ABC\ -\ echilateral\ \Rightarrow\ AB=BC=AC\\ \\ M\in Int( ABC),\ \ MA=MB=MC\ \Rightarrow M - centrul\ cercului\ circumscris\\ \\ Compar\breve am\ \Delta MAB\ cu\ \Delta MBC:\\ \\ \begin{cases} \ AB=BC\\ \\ \it MA=MC\\ \\ MB-\ latur\breve a\ comun\breve a\end{cases} \stackrel{LLL}{\Longrightarrow}\ \Delta MAB\ \equiv\ \Delta MBC[/tex]
[tex]\it Analog\ se\ arat\breve a:\ \Delta MAB\ \equiv\ \Delta MAC;\ \ \ \Delta MBC\ \equiv\ \Delta MAC[/tex]
