1. Perpendicular Bisector of a Line
How To !

2. Step 1 Place the point of the compasses at one end of the line.
Open the compasses to slightly more than half the length of the line.

4. Step 2
Draw an arc above the line (make it quite long).

6. Step 3
Draw an arc below the line.

8. Step 4 Move the point of the compasses to the other end of the line.
DO NOT change the size of the compasses!

10. Step 5
Draw an arc above the line (it should cross the arc you drew before, if not go back to step 2 and make that arc longer).

12. Step 6
Draw an arc below the line (again, you may need to go back to step 3 if your arcs don’t meet).

14. Step 7
Use a ruler to join the two points where the arcs cross.

16. The End Result
The line you have just drawn cuts the original line AB into two equal pieces.
It crosses the line AB at right angles.
It is also ‘the set of points that are equidistant from A and B’ (if you pick any point on the new line and measure the distance from the point to A and B you will find that they are the same).