2.
[tex]\it Compar\breve a m\ \Delta BDC\ cu\ \Delta CEB:\\ \\ \left.\begin{aligned} sunt\ dreptunghice \ \ \ \ \ \ \ \ \\ \\ \it BC\- \ latur\breve a\ comun\breve a\ \ \ \ \ \ \ \ \\ \\ \it \widehat{ACB}\ \equiv\ \widehat{ABC} \ (ip)\ \Rightarrow \widehat{DCB}\ \equiv\ \widehat{EBC}\end{aligned}\right\}\ \stackrel{IU}{\Longrightarrow}\ \Delta BDC\ \equiv\ \Delta CEB[/tex]