Elementary (basic) constructions with compass and straightedge

Compass and straightedge constructions are geometric procedures that use only an unmarked straightedge and a compass to create points, lines, and circles. No measurements or markings are allowed on the straightedge.

Important properties

• You can construct the perpendicular bisector of a segment.

• You can construct the angle bisector of a given angle.

• You can draw a line parallel to a given line through a point.

• You can construct a circle through three non-collinear points.

• All constructions rely on previously constructed points and lines.