Because it is straight.
Chat with our AI personalities
There are three lines in the figure described. Two of the lines never meet, these are the parallel lines. The third line crosses the other lines, it is the "transversal" line. If the parallel lines are really line SEGMENTS then each can be bisected (cut into two equal lengths) This is what your description states.
So that the arcs constructed are at midpoint of the line segment to be bisected.
That will depend entirely on the angle bisected which has not been given.
Any quadrilateral that is not a parallelogram can have only one diagonal that is bisected by the other.
15 degrees