5. Perpendicular lines

When two lines intersect each other at right angles, they are perpendicular to each other.

 

 

Here, \(\overline{AB}\) and \(\overline{CD}\) meet at right angles to each other. Therefore, \(\overline{AB}\) and \(\overline{CD}\) are perpendicular to each other.

 

When a perpendicular line divides another line into two halves, then it is called a perpendicular bisector.

 

 

We know that \(\overline{AB}\) is perpendicular to \(\overline{CD}\). Also, \(AO = OB\).

 

Thus, \(\overline{CD}\) divides \(\overline{AB}\) into two halves.

 

Therefore, \(\overline{CD}\) is the perpendicular bisector of \(\overline{AB}\).