PLEASE HELP I DON'T KNOW WHAT TO DO

Answer:
6
Step-by-step explanation:
The rise of triangle ABC is 4, to go from 4 to 8 is times 2. The run of triangle ABC is 3, since it needs to be a similar triangle 3x2=6. The run of a similar triangle would be 6.
the answer is 6
if you do not understand something you can always ask me
P.S (sorry for the short response i need to be doing home work due at 11:59 so yeah)
You dont have to give me brainliest btw