Respuesta :
Answer:
[tex]m\angle 4=40^{\circ}[/tex]
Step-by-step explanation:
Angles 6 and 7 are vertical angles (opposit to each other). Vertical angles are congruent, so
[tex]11x+8=12x-4\\ \\11x-12x=-4-8\\ \\-x=-12\\ \\x=12[/tex]
Now,
[tex]m\angle 6=(11\cdot 12+8)^{\circ}=140^{\circ}\\ \\m\angle 7=(12\cdot 12-4)^{\circ}=140^{\circ}[/tex]
Angles 6 and 8 are supplementary angles (add up to 180°), so
[tex]m\angle 8=180^{\circ}-140^{\circ}=40^{\circ}[/tex]
Angles 8 and 4 are corresponding angles. Corresponding angles are congruent, so
[tex]m\angle 4=40^{\circ}[/tex]