Answer
To bisect any segment of a line, arc or a figure simply means dividing that segment into two.
And to bisect an arc, the image below for bisecting an arc AB will help the explanation.
The first step to bisecting an arc is to place the pin end of the compass on each of the ends of the arc, that is, first at point A and then point B,
Then, an arbitrary arc is then drawn for these two cases.
The points where the two arcs drawn meet are then connected to each other using a straight line.
This straight line then bisects the arc AB.
Hope this Helps!!!