Stage: 5 Challenge Level: 
One possibility is to use coordinates. You need to use the
coordinatesof the centroids of the
triangles.
Mathematical reasoning & proof. Manipulating algebraic expressions/formulae. Interactivities. Dynamic geometry. Centroid. Calculating with ratio & proportion. Dividing line in given ratio. Inequality/inequalities. Coordinates. Stage 5 needs dealing with.
Published April 2000.
Copyright © 2007. University of Cambridge. All rights reserved.
NRICH is part of the family of activities in the Millennium Mathematics Project, which also includes the Plus and Motivate sites.
email: nrich@damtp.cam.ac.uk