Ac is tangent to circle o at point c what is the length of ac?

Answer:
The Answer is 12
Step-by-step explanation:
Use Pythagorean theorem. AB=8 and BO=5 We still need to find AO
AO=AB+BO
8+5
AO=13
Now solve for AC
AC^2 + OC^2= AO^2
AC^2+5^2=13^2
AC^2+ 25=169
AC^2=144
AC= 12