Circle Theorems

Play around with these so that you become familiar with the different shapes and patterns.

Interactive animations on circle theorems and corollaries.

Four things to know about angles and circles.

1. The angle at the centre is twice the angle on the circle that marks out the same arc - the diagram below shows different examples of this.

2. Angles  standing on the same arc are equal.

3. The angle in a semi-circle is a right angle (the angle on a diameter is a right angle).

4. The sum of the opposite angles in a cyclic quadrilateral is 180.

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Length and Area

Rectangles, Parallelograms and Triangles
You should know how to calculate the area of each shape.
You can go through five animations here.

Circles
See here.

Remember there is useful information in your tables, see pages 8,9 and 10. Click on each page to see a larger view.

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