George is at a trade show and is trading cards. he started the day with 50 cards, traded 5 of his cards for 1 of billy's cards, traded 2 of his cards for 7 of eloise's cards, and then traded 6 of his cards for 6 of migel's cards. how many cards does he have at the end of the day?

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?