Answer:
The answer to your question is AB = 8 units
Step-by-step explanation:
To solve this problem use proportions and similarity of triangles
Compare ΔABC to ΔADB
Big triangle AB /(AD + DC)
Small triangle AD / AB
Substitution
AB / (4 + 12) = 4 / AB
Simplification
AB / 16 = 4 / AB
AB² = 4(16)
AB² = 64
Result
AB = 8
