Fill in the blank proof !Help!

Question

1. We are given that diagonals segment AB ≅ segment BD.

2.It can be stated that segment AB ≅ segment DC because they are opposite sides of a parallelogram.
3. By the Reflexive Property of Congruence, segment AD ≅ AD.
4. Thus,ΔABD ≅ ____ by the ___ Congruence Postulate.
5. Then ∠BAD ≅ ∠CDA because they are corresponding angles of congruent triangles.
6.Since consecutive angles in a parallelogram are supplementary, m∠BAD + m∠CDA=180°.
7.Therefore, using substitution and the definition of congruent angles, the previous statement can be simplified to conclude that m∠BAD and m∠CDA are both 90°.
8. Thus, parallelogram ABCD is a rectangle by definition of a rectangle.

multiple choice answers:
ABC
BCD
ACD
SSS
ASA
SAS

Answer 1

I assume that the congruent diagonals in (1.) are AC and BD.

 

Then the triangle congruent to ABD would be DCA. I am stressing that the order of the vertexes must match, so the triangles are congruent.

 

The blanks that need to be filled are SSS for congruence and ACD for the triangle.

 

When you post problems like this, it is advisable to post the problem itself, along with all other relevant notes.