1. Given
2. AD is parallel to BC
3. ∠3 ≅ ∠2
4. transitive property of congruence
5. Definition of bisect
This is the concept of geometry, for us to prove the similarity of angles we can use the following postulates:
SAS (side-angle-side)
ASA (Angle side Angle)
SSS (side side side)
AAS (Angle Angle side)
therefore, given that AAA is used to prove similarity, another postulate that can be used to strengthen the postulate is SAS, because we already have the angle sizes, adding more sides will make the prove even stronger since we shall have three corresponding angles plus wo corresponding sides.
The angles w and 80 are inscribed angles in the top left and bottom right corners respectively. They are opposite angles in this inscribed quadrilateral. Because they are opposite angles in the inscribed quadrilateral, they add to 180 degrees.
w+80 = 180
w+80-80 = 180-80
w = 100
Answer: Choice D
