1. Circles

2. The point in the middle of the circle is called the center.

3. The distance from the center to the edge is called the radius.

4. The distance from the edge to the edge through the center is called the diameter.

5. radius radius diameter
The diameter is TWICE as long as the radius. It’s really just a radius plus another radius.
radius
radius
diameter

6. The circumference is the distance all the way around the circle.

7. As the words get longer so do their lengths.
Radius : 5 cm
Diameter : 10 cm
Circumference : 31.4 cm

8. Radius = Diameter = 6 12 6

9. Radius = Diameter = 8 16 16

10. Radius = Diameter = 4 8 4

11. Radius = Diameter = 3 6 6

12. Radius = Diameter = 10 20 10

13. Radius = Diameter = 12 24 12

14. Radius = Diameter = 11 22 22

15. Radius = Diameter = 14 28 14

16. Radius = Diameter = 50
100 50

17. Radius = Diameter = 7 14 14

18. Radius = Diameter = 9 18 18

19. Radius = Diameter = 2 1 2

20. Radius = Diameter = 20 40 20

21. Radius = Diameter = 25 50 50

22. Radius = Diameter =
2.5 5 5