Line Callout 3 (No Border): Circumference

 

 

 


               

 

 

 

            

 

·      Area

        

 

 

 

·      Arcs and Sectors - Terminology

 


 

  An arc is a part of a curve.

  A sector is part of a circle enclosed between two radii. 

  A chord is  a line joining two points on a curve.

 

 

Line Callout 2 (No Border): Minor Arc AB
 

 


 

 

 

 

 

 

 

      

Line Callout 2 (No Border): Minor Sector AOB
Line Callout 2 (No Border): Radius OA
 

 

 

 

 

 

 

 


·      Arcs and Sectors Equation

 

 

 

 

 

 


Example 1 What is the length of arc AB ?

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 



      Example 2.    What is the area  of sector  AOB ?

 

 

 

 

 

 

 

 

 

 

 

 

 

 

   

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


·      Chords, Bisectors and Tangents

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


 

 


·      Pythagoras in a circle

 

     Example 3  What is the value of x ?

 

 

 

 

 

 


                                                    

 

                             

 

 

 

 

 

                 Move the radius down !

 

 


             

 

 

 

 

 

 

 

 

      By Pythagoras’ Theorem

           

 

 

·       The angle in a  semi circle

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


The angle in a semi-circle is 90 °