Answer:
Angle B is 30 degrees
Step-by-step explanation:
Vertical angles are always congruent
Vertical angles are always of same measure. The measure of angle B in this case is evaluated as: [tex]m\angle B = 30^\circ[/tex]
Each of the pairs of the opposite angles made by two intersecting lines are called vertical angles.
They are always of same measure.
We can think about this fact as: "there were two lines overlaying on each other. Then, there was a finite point chosen, from where both decided to rotate by a certain degree. Since angle is measure of rotation, and as vertically opposite sides were equally rotated, so they get same measure:"
Its diagram is attached below. The vertical angles are congruent (denoted by ≅) (which is another way to say that they are of same measure)
Since the angle A and angle B specified in this case are pair of vertical angles, and since measure of angle A = 30 degrees, thus, angle B is also of measure 30 degrees.
The measure of an angle is written by writing small m in its left as: [tex]m\angle B = 30^\circ[/tex]
Therefore, the measure of angle B in this case is evaluated as: [tex]m\angle B = 30^\circ[/tex]
Learn more about vertical angles here:
https://brainly.com/question/10668231
