Answer:
18.1 cm
Step-by-step explanation:
AD segment breakup: 11=4+7
Pythagorean Theorem:
7^2+b^2=16^2
49+b^2=256
x^2=207
b=sqrt(207)
b=3sqrt(23)
Pythagorean Theorem:
11^2+3sqrt(23)^2=c^2
121+207=c^2
328=c^2
18.11=c
So the length of AC is around 18.1 cm