Here
is my library of GSP 4.0 tools.Feel
free to bring them up and play with them if your browser has GSP 4.0 set
up as a helper application.If you
have the earlier version of GSP, these tools won't work.These
are grouped as follows.Just pick
a type of construction that interests you and take a look!

If
you want to run any of these tools, the input is always three points.

Ce ntroid (intersection of medians)

Circumcenter
(intersection of perpendicular bisectors of the sides)

Orthocenter
(intersection of the altitudes)

Incenter
(intersection of the angle bisectors)

Again,
the input for these constructions is the three points necessary to define
a triangle.

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