Let the four angles of a quadrilateral are 7x , 11x , 7x and 11x , respectively . According to the question, 7x+11x+7x+11x=360 ⇒ 36x=360 ∴ x=10 ∴ Angles are 70°, 110°, 70°, 110°. ∵ Face angle of quadrilateral are equal. So, quadrilateral is a parallelogram.