Circle presentation

Maths

1. CIRCLE

2. Introduction - 2-dimension -Circular geometry shape - Set of all point in the plane A circle is…

3. Constructing a Circle Compass is use to create a P erfect C ircle with accurate measurements -To make sure the r (radius) and the d (diameter) are the same at all points

4. Circle Arc -A closed segment of a curve Sector -A region of a circle which is "cut off" from the circle by a chord Segment -A portion of a disk enclosed by two radii and an arc

5. Circle Radius- A distance from the center of the circle to any point of the circumference Diameter -A distance between two point passing through the center Circumference -Linear distance around the edge of a closed curve

6. Piiiiiiii… Do You Know… Pi is a irrational number since its value is not proportion Pi has 18 digit decimal place -which is 3.1415926535 89793238

7. Circumference In which π =22/7 or 3.142 -C =2 π r or π d

8. Circumference Example: You walk around a circle which has a diameter of 100m, how far have you walked? Distance walked = Circumference = π × 100m = 314m (to the nearest m) -Using the formula of πd

9. Arc Length s =arc length of the circle r =radius =degree/radian (converted) Arc, s=r0

10. Arc Length s =r0 s =9 ( 1.05 rad ) s =9.424 cm Example:

11. Area of the Sector s =sector of the circle r =radius =degree/radian

12. Area of the Sector s =1/2r 2 s =1/2(24) 2 ( 2.095 rad ) s =603.072 cm 2 Example:

13. Area of the Segment Area of Segment=Area of sector-Area of triangle r 2 (0-sin 0) r =radius =degree/radian

14. Area of the Segment s =1/2 r 2 (0-sin 0) s =1/2(7) 2 ( 1.746 rad ) -sin ( 1.746 rad) s = 42.01 cm 2 Example:

15. SPHERE

16. Introduction A s phere is… -3 Dimension -Circular in shape -Rounded ball surface completely

17. Surface Area A=4 π r 2 A =Surface area r =Radius

18. Surface Area A =4 π r A =4(22/7)(5) 2 A =314.29cm 2

19. Volume V= π r 3 V =Volume r =radius

20. Volume V =4/3 (22/7)(8)3 V =2145.52cm 3