Question

What is the length of DB?

A. 5.3
B. 5
C. 6.6
D. 6.3

(adding picture)

Answer 1

Ok, ready to do some work?

Answer 2

Lets go

At first we can find AD,
5^2-4^2=AD ^2
AD=3

Answer 3

Now, lets find angle DCA,

Answer 4

solve for x.
@TheScholarlyApproach