Question

answer this please friends

Answer 1

A + B=180° therefore it is an cyclic quadrilateral . so the angle D or vertex D should also lie on the same circle as it is a cyclic quadrilateral

Answer 2

GIVEN- A, B, C are Vertices of quadrilateral lies on circle

angle A+ angle C=180

TO PROVE - D is on the circle

PROOF-

as we know that the sum of measures of angles of quadrilateral is 360

angle A+angle C+angleB+angle D=360

180+angle B+angle C=360

angle B+angle C=180

see sum of measures of opposite angles is 180 so it must be cyclic quadrilateral

so point D lie on circle