Quadrilateral abcd is inscribed in circle o. what is m∠b ? enter your answer in the box. ° a quadrilateral is inscribed in a circle o. the vertices of the quadrilateral lie on the edge of the circle and are labeled as a, b, c, and d. the interior angle a is labeled as left parenthesis 2 x minus 7 right parenthesis. the angle b is labeled as left parenthesis 2 x plus 3 right parenthesis. the angle c is labeled as left parenthesis x plus 4 right parenthesis.