Question

Please help I have been trying to solve this

Answer 1

The intersecting chord theorem says

$AY \cdot BY = CY \cdot DY$

$AY = \dfrac{ CY \cdot DY}{BY} = \dfrac{6 \cdot 12}{9} = 8$

$AB = AY + BY = 8 + 9 = 17$

Answer: 17