Parts of a Circle

• Circle: a set of all points that are equidistant from another single point called the center.

  
  

• r = radius ; D = diameter

  Diameter = 2 x radius or D = 2r

   radius=Diamater/2 or r=D/2

  
  

• Watch the video https://www.youtube.com/watch?v=cC0fZ_lkFpQ

An Important Question

Circumference and Area

• Circumference = π ×Diameter

  C =πD

  Since D=2xr then C=2πr

     

  Area =π ×radius ×radius

  or A=π x r^2

  A=π x r2

    

• https://www.youtube.com/watch?v=cC0fZ_lkFpQ