Ten pounds of mixed birdseed sells for 8.24 per pound. the mixture is obtained from two kinds of birdseed, with one variety priced at 5.68 per pound and the other at 8.88 per pound. how many pounds of each variety of birdseed are used in the mixture?

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?