In the given panel below click at any three points O, A and C. Click on the
button "Show OAC" to display the triangle OAC. Click on the button "Midpoints
P, Q, R" to draw the mid points of the Line O, A and C. You can change the triangle by moving either of the (red) points O, A or
C. Click on the button 'Medians' to see that the medians are concurrent, and stay concurrent even
when O, A or C are moved. Click at 'Ratio Index' to see that S divides a median in the ratio 2:1.
Remember to drag the points O, A or C before changing the 'Ratio Index'.|