Explanation:
A cyclic quadrilateral is a quadrilateral whose vertices all lie on a single circle. A convex quadrilateral ABCD is cyclic if and only if its opposite angles are supplementary, means
∠q + 58 =180
∠q = 180 -58
∠q = 122 degree
∠p + 90 = 180
∠p = 180 -90
∠p = 90 degree