Question

can a quadrilateral ABCD a parallelogram if angle D plus angle B equal to 180

Answer 1

Only this is not enough , its all sides should be parallel to each other

Answer 2

If /_ D+ /_ B= 180...... Then the quadrilateral is not a parallelogram.......... In a llgm , opp. sides should be parallel and equal... And both the pairs of opp. angles should be equal., Sum of consecutive angles should be 180, and if 1 angle is 90° then the rest other angles should also be 90 °,,