Answer:
∠B = 52°.
Step-by-step explanation:
Given: m∠A=(8x-4)° and m∠B=(7x+3)°. ∠A and ∠B are vertical angles.
Since ∠A and ∠B are vertical angles. So, there measure are equal.
[tex]m\angle A=m\angle B[/tex]
[tex](8x-4)^{\circ}=(7x+3)^{\circ}[/tex]
[tex]8x-4=7x+3[/tex]
[tex]8x-7x=4+3[/tex]
[tex]x=7[/tex]
Now,
[tex]m\angle B=(7(7)+3)^{\circ}[/tex]
[tex]m\angle B=(49+3)^{\circ}[/tex]
[tex]m\angle B=52^{\circ}[/tex]
Therefore, the measure of ∠B is 52°.