Answer:
Determine AC with the pythagorean theorem, then you can find CD by subtracting AD.
with DC and BC, you can find BD. again, with the pythagorean theorem
20
Step-by-step explanation:
Find AC
[tex]\sqrt{65^{2} -16^{2} } = 63[/tex]
Substract
63 - AD = 12
Find "?"
[tex]\sqrt{12^{2} +16^{2} } = 20[/tex]
