The first way of making bisect perpendicular lines.
1.Draw a line segment on a piece of paper.

2.Make the ends of the line segment point A and point B.
3.Fold the paper so point A is exactly on top of point B.
4.Draw a line down the crease that you have made.

5. Now you can input your right angle in the top right box or the bottom left.
The second way of making bisect perpendicular lines.
1.Using a right triangle draw a line segment on a piece of paper.
2.Still using the right triangle find half of the line segment that you made and make a little mark.
3.Using the right angle of your triangle make another line segment intersecting your original one.
4.Now you can make your ninety degree mark for your right angle.
The third way to make a bisect perpendicular line.
I just found a video to help you with perpendicular lines using a compass.
Just click on this link.
http://www.youtube.com/watch?v=QT28JgIep48I hope you found my scribe post helpful!