Question Number 141972 by iloveisrael last updated on 25/May/21
Commented by Dwaipayan Shikari last updated on 25/May/21
$${x}°+\mathrm{20}°+\left(\mathrm{360}°−\mathrm{140}°\right)+\mathrm{90}°=\mathrm{360}° \\ $$$$\Rightarrow{x}°=\mathrm{30}° \\ $$
Commented by I want to learn more last updated on 25/May/21
$$\mathrm{90}\:\:+\:\:\mathrm{x}\:\:+\:\:\mathrm{20}\:\:\:=\:\:\:\mathrm{140} \\ $$$$\therefore\:\:\:\:\:\mathrm{x}\:\:\:+\:\:\mathrm{110}\:\:\:=\:\:\:\mathrm{140} \\ $$$$\therefore\:\:\:\:\:\mathrm{x}\:\:\:=\:\:\mathrm{140}\:\:\:−\:\:\:\mathrm{110} \\ $$$$\therefore\:\:\:\:\:\mathrm{x}\:\:\:=\:\:\mathrm{30} \\ $$