[tex]\boxed{2 \alpha + \alpha + \alpha +20 \textdegree = 180 \textdegree} \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \textnormal{ - Rownanie }}\\\\ \boxe4 \alpha + 20 \textdegree = 180 \textdegree \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ / - 20\textdegree \\4 \alpha = 160 \textdegree \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ /:4 \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \textnormal{- Rozwiazanie rownania } \\\alpha = 40 \textdegree[/tex]
