Math Teaching on Properties of Circles

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Properties of Circles

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Monday, July 20, 2009

Teaching Concept Two

Let us look at the 1st Symmetrical Property of Circles:
- The chord of a circle that passes through the centre of the circle is called the Perepndicular Bisector.
- Therefore, in equal circles or in the same circle, equal chords are equidistant from the centre.
- In another words, chords which are equidistant from the centre are equal.
- With this property, we are able to locate the centre of the circle.

- How to proof if the chords are always equidistant?
Proof:
- In the figure below, triangle OAB is rotated through an angle AOA' to triangle OA'B' about O.
- Since rotation preserves the shape and size, AB = A'B' and OG = OH. [Proven]

- Let us try a Simple Question.
If you are a designer for the construction of the Ferry Wheel in Genting Highland, using this property which you have just learnt, explain how would you find the centre of the Flyer?

# posted by Properties of Circles at 2:54:00 AM