Answer:
x = 5
Step-by-step explanation:
m∠C ≅ m∠ABD and ∠A = ∠A
ΔABC similar to ΔADB
AB / AD = AC / AB
6 / 4 = (AD + CD) / 6 = (4 + x) / 6
4 x (4 + x) = 6 x 6
16 + 4x = 36
4x = 20
