Two sets of points - A, B, C and A',B',C' are drawn on an ellipse.[br][[b][size=85]you can adjust the size and shape of the ellipse by dragging the purple dots[/size][/b]][br][br]The following sets of lines are drawn - [br] AB' and BA'[br] AC' and CA'[br] BC' and CB'[br][br]Each of these sets of lines intersect at a point.[br][br]Drag the points to persuade yourself that the three intersection points always lie on a straight line.[br][br]Can you explain why this is so?[br][br][color=#ff0000][i][b]What questions could/would you put to your students based on this applet?[/b][/i][/color]