[tex]\\ \sf\longmapsto x+90+3x=360[/tex]
[tex]\\ \sf\longmapsto 4x+90=360[/tex]
[tex]\\ \sf\longmapsto 4x=360-90[/tex]
[tex]\\ \sf\longmapsto 4x=270[/tex]
[tex]\\ \sf\longmapsto x=\dfrac{270}{4}[/tex]
[tex]\\ \sf\longmapsto x=67.5[/tex]
x = 67.5°
Step-by-step explanation:
[tex]\begin{aligned}\tt 3x+x&=\tt 270^\circ\\\tt 4x&=\tt 270\\\tt x&=\tt\frac{270}{4}\\\tt x&=\tt\frac{135}{2}\\\tt x&= \underline{\underline{\tt 67.5^\circ}}\end{aligned}[/tex]
