1. 1

2. 2 Circle A circle is the set of all points that are the same distance from a given point called the center.

3. 3 Center The given point from which all points on a circle are the same distance.

4. 4 Circumference The distance around a circle.

5. 5 Diameter The diameter of a circle is a line segment that joins any two points on the circle and passes through the center of the circle.

6. 6 Radius The radius of a circle is a line segment joining the center of the circle and any point on the circle.

7. 7 diameter radius circumference diameter = 2 times radius of diameter radius =

8. 8 8cm r = d ÷ 2 r = 8 ÷ 2 r = 4 cm 6 yd Find the radius. Find the diameter. d = 2r d = 2۰6 d = 12 yd

9. 9 The relationship of the circumference and the diameter of a circle is called pi. The symbol for pi is.

10. 10 Think of fact families Circumference

11. 11 Circumference WORDS: The circumference of a circle is equal to pi times its diameter or pi times twice its radius. Symbols: or

12. 12 Circumference Symbols: or

13. 13 The circumference of a circle is a little more than three times its diameter. The circumference of a circle is a little more than six times its radius.

14. 14 Use. Find the circumference. 8cm

15. 15 Use. Find the circumference. 4 ft

16. 16 Use. Find the circumference. 6 mm 6 x 6

17. 17 Use. Find the circumference. 7 mm 6 x 7