Compass and Straightedge Constructions with videos:


Basic Constructions:


Triangle centers:


Orthocenter - Altitudes ( vertex perpendicular to opposite side)

Circumcenter - Perpendicular bisectors of sides - a circle with the circumcenter as its center will circumscribe the triangle

Incenter - Angle bisectors - a circle with the incenter as its center will be inscribed in the circle

Centroid - Medians (vertex to midpoint of opposite side)

The Euler Line -  orthocenter, centroid, circumcenter, (also incenter when isosceles)