Question

In a quadrilateral abcd angle a + angle b is equal to 180 degree does this means a b is parallel to dc why what special name does a quadrilateral have

Answer 1

If adj. angles of a quadrilateral are complimentary the quadrilateral is considered to be a parallelogram.

angle A + angle B = 180 (given)
therefore,
angle C + angle D = 180 (360-A+B)

Thus, the given quadrilateral is a parallelogram.

Answer 2

HERE IS UR ANSWER DEAR,

if adjacent angles of a quadrilateral are complementary angles then it is said to be parallelogram