Circumcenter
Incenter
Orthocenter all
four points together
Angle bisector instructions
Perpendicular bisector instructions
Median instructions
Altitude instructions
Period
3 Period 4
Period 5
Centroid
Construction of the medians of a triangle are easy if you know how to
construct a perpendicular bisector.
Once you have found the midpoint of each side then draw the median
from the vertex to the opposite midpoint.
The intersection of the medians is the centroid.
The centroid is the center of gravity.