# Constructing perpendicular at a point on a line

This is the step-by-step, printable version. If you PRINT this page, any ads will not be printed.

After doing this Your work should look like this
Start with a line and point K on that line.
1 Set the compasses' width to a medium setting. The actual width does not matter.
2 Without changing the compasses' width, mark a short arc on the line at each side of the point K, forming the points P,Q. These two points are thus the same distance from K.
3 Increase the compasses to almost double the width (again the exact setting is not important).
4 From P, mark off a short arc above K
5 Without changing the compasses' width repeat from the point Q so that the the two arcs cross each other, creating the point R
6 Using the straight edge, draw a line from K to where the arcs cross.
7 Done. The line just drawn is a perpendicular to the line at K
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