Question

Melissa’s proof

1. For triangles AOB and DOC, angle 1 is equal to angle 2 as they are vertical angles.
2. AO = OC and BO = OD because it is given that diagonals bisect each other.
3. The triangles AOB and DOC are congruent by SSS postulate.
4. Similarly, triangles AOD and BOC are congruent.
5. By CPCTC, AB is equal to DC.
6. By CPCTC, AD is equal to BC.
7. As the opposite sides are congruent the quadrilateral ABCD is a parallelogram.

Which is the first incorrect statement in Melissa’s proof?

Answer 1

Statement 5

Statement 3

Statement 4

Statement 6

Answer 2

Look at Statement 3:
its not by SSS, what should it be?

Answer 3

ASA?

Answer 4

based on what you know from statements 1 and 2, you only know 1 angle so it can't be ASA