Question

in a quadrilateral ABCD angle A + angle d is equal to 180 degree does it mean ab parallel to dc why? what special name does this quadrilateral have?

Answer 1

1. Answer: ∠ A = 90° and ∠ D = 90°

∠A+∠D =180°

90°+90°=180°

∴AB║DC

∵ quadrilateral ABCD is a parallelogram.

Step-by-step explanation:

Answer 2

Answer:

Trapezium

Step-by-step explanation:

Since, ABCD is a quadrilateral and ∠A+∠D= 180°.

From the figure, we can see that ∠A and ∠D form the adjacent angle pair and it is already known that the two adjacent angles always add to give their angle sum equal to 180°.

Also, adjacent angles are formed if the two lines are parallel which means that if two adjacent angles are given then the two ,lines must be parallel, therefore AB  is parallel to CD.

If the two lines are parallel and also, the angle sum of two adjacent angles equal to 180°, then this type of quadrilateral is known as "Trapezium".