Did i do this correctly? if i didnt what did i do wrong?

Can some one explain this i got sent this. is this a threat i’m scared

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?

The slope of cd is which segments are perpendicular to cd ? select each correct answer. gf , where g is at (6, 5)and fis at (10, 2) ef, where e is at (4, 1) and f is at (7,5) lm , where lis at (-2, 3) and m is at (-10, 9) jk , where jis at (1, -2) and k is at (10, – 14) next