Which of the following is required for constructing the line of symmetry when two fixed points are symmetric with respect to the required line?
Perpendicular bisector of the given line
Let A and B be the two fixed symmetric points. Join A and B.
Draw a perpendicular bisector of this line.
Mark the ends of the perpendicular bisector PQ.
This line PQ is called the line of symmetry or axis of symmetry of the line AB.