Answer:
DC = 3
Step-by-step explanation:
Based on triangle similarity theorem, we would have the following equation:

Plug in the values



Cross multiply
3(9 + DC) = 9×4
27 + 3DC = 36
Subtract 27 from each side
3DC = 36 - 27
3DC = 9
Divide both sides by 3
DC = 9/3
DC = 3
Answer:
D
Step-by-step explanation:
every 2 sides of a triangle has to be bigger than the 3rd side
They are similar,
translation and rotation