Answer:
D.
Step-by-step explanation:
first, classic pythagoras with the smaller triangle.
3² + 4² = 25
sqrt 25 = 5
ok ok, now
5 can be turned into 15 by multiplying 3. do this with 4 and 3 to make the full triangle.
3 -> 9 (line AE)
4 -> 12 (line DE)
5 -> 15 (line AD)
