We can clearly see the graph of an ellipse ‘e’ in red. Its foci and a point on the circumference are given. A and B are the two foci of the ellipse and C is a point present on its circumference. We can freely move these three points A, B and C. When we move these points then the shape, size and position of the ellipse gets altered. Let us change the positions of A, B and C and observe how the shape of the ellipse changes

Questions to think about
1. Let us change the positions of the three points A, B and C and observe how the shape and position of the ellipse gets altered.
2. How many ellipses are possible when a pair of foci and one point on the circumference are given?
3. What doyou observe when A and B overlap each other