Answer: The correct answer is option B: The vertical angle
Step-by-step explanation: Please refer to the picture attached for further details.
The circle with center O has an arc AB with a central angle of 42 degrees as shown in the diagram (not draw to scale).
If the line A is extended to point D and also line B is extended to point C both along the circumference of the circle O, then you would have another arc CD on the circle.
If two intersecting lines AD and BC form a pair of angles (shown here as 42° and x°) the angles are called vertical angles, and vertical angles in a circle are equal.
Hence the only thing that can be shown to measure 42 degrees in the question above is a vertical angle.
