(please help!! ) The diagonals of parallelogram ABCD intersect at P. Select all the statements that must be true.
A. AP¯¯¯¯¯¯ ≅ CP¯¯¯¯¯¯
B. BC¯¯¯¯¯¯ ≅ AD¯¯¯¯¯¯
C. m∠ABC=90
D. ∠CAD ≅ ∠ACB
E. ∠BPC ≅ ∠APD

Given: ab ≅ cd and ad ≅ bc prove: abcd is a parallelogram. statements reasons 1. ab ≅ cd; ad ≅ bc 1. given 2. ac ≅ ac 2. reflexive property 3. △adc ≅ △cba 3. ? 4. ∠dac ≅ ∠bca; ∠acd ≅ ∠cab 4. cpctc 5. ∠dac and ∠bca are alt. int. ∠s; ∠acd and ∠cab are alt. int. ∠s 5. definition of alternate interior angles 6. ab ∥ cd; ad ∥ bc 6. converse of the alternate interior angles theorem 7. abcd is a parallelogram 7. definition of parallelogram what is the missing reason in step 3? triangle angle sum theorem sas congruency theorem sss congruency theorem cpctc