Geometry construction using a compass and straightedge

This page shows how to construct a
perpendicular
to a line through an external point, using only a compass and straightedge or ruler. It works by creating a
line segment
on the given line, then
bisecting it. The bisector
will be a right angles to the given line. (See proof below).

Click here for a printable construction worksheet containing two 'perpendiculars through a point' problems to try.
When you get to the page, use the browser print command to print as many as you wish. The printed output is not copyright.