If the are length of a circle with arc measure of 140 degrees is 18pi find the circumference and area of the circle

Question

I'm not sure where to begin with this question.

Answer 1

 

140/360 * pi * diameter = 18*pi

 

diameter = 18*pi*360 / (140*pi)

 

              = 6480*pi /( 140 * pi)

 

               = 648/14

 

                = 324/7

 

Circumference = pi * diameter = 324*pi/7

 

For Circumference, You can also do:

 

 

   140            360

-------- = ------------

  18*pi            ?

 

140 * ? = 360 * 18 * pi

 

        ? = 360 * 18 * pi / 140

 

           = 324/7 * pi

 

 

The radius is 162/7

 

Area = pi * radius^2  = pi * (162/7)^2

 

                                = 26244*pi/49