Czołem!
α + ½α + α = 180°
2,5α = 180° | : 2,5
α = 72°
β + β - 30° + 90° = 180°
2β + 60° = 180°
2β = 180° - 60°
2β = 120° | : 2
β = 60°
γ + γ + 10° + γ - 10° = 180°
3γ = 180° | : 3
γ = 60°
