8- F 7-- 6- C 5 4- D E 3- A B X O- Statement Reason 1. AABC and ADEF are similar. given BC AB 2. EF = DE Property of Similar Triangles AB DE 3. BC = EF Property of Proportion 4. slope of line AC: BC definition of slope AB 5. slope of line DF: EF definition of slope DE 6. Substitution Property of Equality10 The table contains the proof of the theorem of the relationship between slopes of parallel lines. What is the missing statement for step 6? O A. slope of AC = -- slope of DF O B. slope of AC = slope of DF O C. slope of AC = - slope of DF O D. slope of AC = slope of DF O E. slope of AC = 1 - slope of DF Reset Next