Option B: 1
Option C: 6
Solution:
Let us first define the vertical angle theorem:
Vertical angle theorem:
If two lines are intersecting each other, then the vertically opposite angles are congruent.
To find angle 7 is equal to which angle:
Angle 1 and angle 7 are vertically opposite angles.
Therefore by vertical angle theorem, angle 7 = angle 1
Option B is the correct answer.
To find angle 4 is equal to which angle:
Angle 4 and angle 6 are vertically opposite angles.
Therefore by vertical angle theorem, angle 4 = angle 6
Option C is the correct answer.