Ce ntroid (intersection of medians)
Circumcenter
(intersection of perpendicular bisectors of the sides)
Incenter
(intersection of the angle bisectors)
Medial
Triangle (formed by connecting the midpoints of the sides of a given
triangle)
Orthocenter,
Mid-segment triangle
Nine
Point Circle (constructed by finding the center of a circle that passes
through the 3 mid-points of the sides, the 3 feet of the altitudes and
the 3 midpoints of the segments from the triangle vertices to the orthocenter)
Orthic
Triangle (constructed by connecting the feet of the altitudes)
Pedal
Triangle (for more information on pedal triangles, see write up #9)
Isosceles
Triangle Given a Base and Altitude
Regular
Pentagon Given the Apothem
Regular
Pentagon Given a Side AB
Regular
Hexagon Given a Side AB