In the given figure, ΔABC is an equilateral triangle and ABDC is a cyclic quadrilateral, then find the measure of ∠BDC. -Maths 9th

In the given figure, ΔABC is an equilateral triangle and ABDC is a cyclic quadrilateral, then find the measure of ∠BDC. -Maths 9th
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Answer :

△ABC is an equilateral triangle.  ∠BAE=60 ABEC is a cyclic quadrilateral. We know, ∠BAC+∠BEC=180 =>∠BEC=180−60                        =120 We know that the angles subtended by an arc on the  circumference on the same side are equal. Therefore, ∠ABC=∠BDC =>∠BDC=60
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