In Fig. 16.185, if ABC is an equilateral triangle. Find BDC and BEC

Since, ABC is an equilateral triangle

Then,


BAC = 60o


Therefore,


BDC = BAC = 60o (Angles in the same segment)


Since, quadrilateral ABEC is a cyclic quadrilateral


Then,


BAC + BEC = 180o


60o + BEC= 180o


BEC = 180o – 60o


= 120o


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