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I am trying desperately to solve following problem. How can I solve it, the image and question is included in image
1 Answer
$\begingroup$Since $\square ABCD$ is a cyclic quadrilateral, $m\angle ADC + m\angle ABC = 180^\circ \implies m\angle ADC = 180^\circ - 100^\circ = 80^\circ$, using this.
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