#### Question

Can a quadrilateral ABCD be a parallelogram if ∠D + ∠B = 180°?

#### Solution

For ∠D + ∠B = 180°, quadrilateral ABCD may or may not be a parallelogram. Along with this condition, the following conditions should also be fulfilled.

The sum of the measures of adjacent angles should be 180º.

Opposite angles should also be of same measures.

Is there an error in this question or solution?

Solution Can a Quadrilateral Abcd Be a Parallelogram If ∠D + ∠B = 180°? Concept: Kinds of Quadrilaterals - Elements of a Parallelogram.