In the figure, AB is tangent to circle C. Find the length of DB.

Answer:
8.5
Step-by-step explanation:
First we need to get BC using the pythagoras theorem
BC² = AC² + AB²
BC² = 8² + 15²
BC² = 64+225
BC² = 289
BC = √289
BC = 17
DB = 1/2BC
DB = 1/2 * 17
DB = 8.5
Hence the length of DB is 8.5