Verified answer

❑ solution

[tex]\green {x + 2x = 180 \: degree}[/tex]

[tex]\bold{co \: interior}[/tex]

[tex]\bold{co \: interrior \: sum \: is \: 180 \: degree}[/tex]

[tex]\green{3x = 180 \: degree}[/tex]

[tex]\green{x = \frac{180}{3} }[/tex]

[tex]\green{x = \frac{180}{3} } = 60[/tex]

[tex]{\red{\mathfrak{x = 60 \: degree}}}[/tex]

Hope it helps