1. Everybody knows these are NOT circles. But why?
Can you come up with a definition of a circle?

2. Definition of a circle
It is the set of all points in a plane that are at a given distance from a given point, the centre

3. Definition of a circle
The given distance from the centre is called the radius

4. A line that crosses the circle and goes through the centre point is called the ? diameter

5. The part of a circle separated by two radii is called a sector

6. The curved part of a sector is called an arc

7. A line that crosses the circle and but doesn’t go through the centre point is called a ? chord

8. A chord cuts a circle into ? segments

9. The distance around the outside is called the ? circumference.

10. Label these circles with these key words:
radius, diameter, arc, chord, segment, sector, circumference

11. Draw:
A circle with a radius of 5cm
A circle with a diameter of 5cm
Concentric circles where one radius is half the other
A semi-circle with a diameter of 7cm
Any sector with radius 4cm
A sector with a radius of 5cm and angle 300

12. Draw these diagrams.
Write instructions for someone else to draw these diagrams.