Notăm măsurile celor trei unghiuri cu x, y, z.
[tex] \it \dfrac{x}{2}=\dfrac{y}{3}=\dfrac{z}{5} =\ \dfrac{x+y+z}{2+3+5} = \dfrac{180^o}{10} =18^o
\\ \\ \\
\dfrac{x}{2}=18^o \Rightarrow x = 2\cdot18^o =36^o
\\ \\ \\
\dfrac{y}{3}=18^o \Rightarrow y = 3\cdot18^o =54^o
\\ \\ \\
\dfrac{z}{5}=18^o \Rightarrow z = 5\cdot18^o =90^o
\\ \\ \\
90^o-36^o=54^o [/tex]
