This activity helps the student to establish the relationship between two equal chords of a circle and its distance from the centre.

1) Observe the length of CD and EF[br]2) As you change the length of CD by moving the points either C or D, Observe the lengths of CD and EF[br]3) Change the position of EF by moving E and note the length of CD and EF[br]4) From (2) and (3) , how CD is related to EF?[br]5) Observe ∠OMC and ∠ONE. [br]6) What can you say about the points M and N? [br]7) Why?[br]8) Examine the values of OM and ON as you repeat step (2) or (3).. [br]9) What can you observe?[br]10) Change the radius of the circle by moving the position of O[br]11) Repeat the procedure[br]12) Note down your observation.[br]13) Frame the theorem based on your observation.