It is angle measure please help

Opposite angles are equal
[tex]\\ \rm\longmapsto m+357=4m+6[/tex]
[tex]\\ \rm\longmapsto 357-6=4m-m[/tex]
[tex]\\ \rm\longmapsto 3m=351[/tex]
[tex]\\ \rm\longmapsto m=\dfrac{351}{3}[/tex]
[tex]\\ \rm\longmapsto m=117[/tex]