A chord of a circle of radius 12 cm subtends an angle of 120° at the centre. Find the area of the corresponding segment of the circle


(Use π = 3.14 and √3 = 1.73)


Let us draw a perpendicular OV on chord ST. It will bisect the chord ST and the angle O.


SV = VT


In ΔOVS,


= Cos 60o


=


OV = 6 cm


= Sin 60o


=


SV = 6√3 cm


ST = 2 * SV


= 2 * 6√3


= 12√3 cm


Area of ΔOST = * 12√3 * 6


= 36√3


= 36 * 1.73


= 62.28 cm2


 


Area of sector OSUT = * π * (12)2


 


= * 3.14 * 144


 


= 150.72 cm2


 


Area of segment SUT = Area of sector OSUT - Area of ΔOST


 


= 150.72 - 62.28


 


= 88.44 cm2


 

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