Answer:
m∠B=143°
Step-by-step explanation:
we know that
Vertical Angles are the angles opposite each other when two lines cross. They are always equal
so
In this problem we have that
m∠A=m∠B ----> by vertical angles
substitute the given values and solve for x
[tex](4x+23)=(5x-7)\\5x-4x=23+7\\x=30[/tex]
Find the measure of angle B
m∠B=(5x-7)°
substitute the value of x
m∠B=(5(30)-7)°
m∠B=143°