What is the value of a?
✅6√2
❌9
❌8√3
❌36√2

Answer:
6√2.
Step-by-step explanation:
Triangles CDE and DBE are similar.
Therefore:
a / 18 = 4 / a
a^2 = 4*18
a^2 = 72
a^2 = 36*2
a = √36*√2
a = 6√2.