Answer:
x = 6 and DF = 3*6-3 = 15
Step-by-step explanation:
Given triangles are similar and their side lengths are proportional
the similarity ratio for this pair is 4/8 = 1/2
the length of DF:
(7.5)/(3x - 3) = 1/2 cross multiply expressions
3x - 3 = 15 add 3 to both sides
3x = 18 divide both sides by 2
x = 6 and DF = 3*6-3 = 15
