Answer:

d. 180°

Step-by-step explanation:

I hope this helps.

Answer:

d. 180°

Step-by-step explanation:

The angles of a quadrilateral are in formed of two triangles and the sum of its triangle of it is 180° so that's the answer and one more thing, if you divide the quadrilateral into two there'll be two triangles so that's why it is 180°