Ng Kellen is saving for retirement. He deposits $325 each month at 3.2% annual interest for 20 years. According to his
calculations, at the end of 20 years he should have $109, 061.81 in his account. How much of this did Kellen
contribute and how much of this is interest?

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?