Question

How do we know that OR is the perpendicular bisector for PQ in example 3 of circles lesson?​

Answer 1

A line which cuts a line segment into two equal parts at 90°. Try this Drag one of the orange dots at A or B and note the the line AB always divides the segment PQ into two equal parts. When it is exactly at right angles to PQ it is called the perpendicular bisector.

A perpendicular bisector of a line segment passes through the midpoint of the line segment and intersects the line segment at 90^\circ. If a point is equidistant from the endpoints of a segment, then the point is on the perpendicular bisector of the segment.

its the answer....