This applet walks through the ruler and compass construction of a line perpendicular to a given line through a given point C, on the line.
Drag the Steps slider to see the steps of the construction. The construction assumes that the user has already worked through the construction of the perpendicular bisector of a line segment.

Drag the Steps slider to see the steps of the construction. The construction assumes that the user has already worked through the construction of the perpendicular bisector of a line segment.
The two points, A and B, which define the line, and the given point C, can be moved to new positions by dragging.