Question Number 186069 by TUN last updated on 31/Jan/23
Answered by HeferH last updated on 31/Jan/23
$$\alpha=\mathrm{10}° \\ $$
Commented by HeferH last updated on 31/Jan/23
Commented by HeferH last updated on 31/Jan/23
$$\mathrm{2}\left(\mathrm{120}°\:−\:\mathrm{4}\alpha\right)\:+\:\mathrm{2}\alpha\:=\:\mathrm{180}° \\ $$$$\mathrm{240}°\:−\:\mathrm{6}\alpha=\mathrm{180}° \\ $$$$\:\alpha\:=\:\frac{\mathrm{60}°}{\mathrm{6}}\:=\:\mathrm{10}° \\ $$