Geometry

 

The area of a shaded sector of the circle is 108pi square centimeters.     

Given an arc measure of 120, what is the length of the radius in centimeters?     

 

120^o is a third of 360^o so the area of the entire circle is 3 • 108π = 324π     

 

                                           A  = π r²     

                                     324π  =  π r²     

divide both sides by π        r²  = 324     

                                           r¹  =  sqrt(324)     

                                           r    =  18     

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