[tex] \alpha + \alpha + θ + \alpha + 2θ = 180° \\ 3 \alpha + 3θ = 180° \\ 3( \alpha + θ) = 180° \\ \alpha + θ = \frac{180°}{3} \\ \alpha + θ = 60°[/tex]
[tex]x = \alpha + θ \\ x = 60°[/tex]
