Congruent chords are equidistant from the centre of a circle

Estimated Time

40 minutes

Prerequisites/Instructions, prior preparations, if any

Basics of circles and its related terms should have been done.

Materials/ Resources needed

Laptop, geogebra,projector and a pointer.

This geogebra file has been created by Tharanath Achar of Dakshina kannada.

Process (How to do the activity)

Developmental Questions

1. What is a chord ?
2. Name the centre of the circle.
3. How do you draw congruent chords in a circle ?
4. How many chords do you see in the figure ? Name them.
5. If both the chords are congruent, what can you say about the length of both the chords ?
6. How can we measure the length of the chord ?
7. What is the procedure to draw perpendicular bisector ?
8. What does theorem 1 say ? Do you all remember ?
9. What is the length of both chords here ?
10. What can you conclude ?
11. Repeat this for circles of different radii and for different lengths of congruent chords.

• Evaluation Questions

1. Were the students able to comprehend the drawing of congruent chords in a circle ?
2. Were the students able to comprehend why congruent chords are always equal for a given circle. Let any student explain the analogy.
3. Are the students able to understand that this theorem can be very useful in solving problems related to circles and triangles ?
4. What is a chord ?
5. What are congruent chords ?
6. Why do you think congruent chords are always equal for a circle of given radius ?