[tex]\it Fie\ x,\ y,\ z\ m\breve asurile\ celor\ trei\ unghiuri\ ale\ triunghiului.\\ \\ x+y+z=180^o\ \ \ \ \ \ (*)\\ \\ \{x,\ y,\ z\}\ d.\ p.\ \{3,\ 4,\ 5\} \Rightarrow \dfrac{x}{3}=\dfrac{y}{4}=\dfrac{z}{5}=\dfrac{x+y+z}{3+4+5}\ \stackrel{(*)}{=}\ \ \dfrac{180^o}{12}=15^o\\ \\ \\ \dfrac{x}{3}=15^o \Rightarrow x=3\cdot15^o=45^o \\ \\ \\ \dfrac{y}{4}=15^o \Rightarrow y=4\cdot15^o=60^o\\ \\ \\ \dfrac{z}{5}=15^o \Rightarrow z=5\cdot15^o=75^o[/tex]
