Answer:
AC = 18.1 cm
Step-by-step explanation:
Construct a line from point B perpendicular to the line AD and mark it as E on line AD. Now you have a right triangle ABE with AB = 16 cm and AE = AD - BC
so AE = 11 cm - 4 cm = 7 cm
You can find BE by using Pythagorean theorem
BE^2 = AB^2 - AE^2
BE^2 = 16^2 - 7^2
BE^2 = 256 - 49
BE^2 = 207
BE = 14.4 cm
Draw a line from A to C, you have a right triangle ACD with AD = 11cm and CD = BE = 14.4 cm
Using Pythagorean theorem
AC^2 = AD^2 + CD^2
AC^2 = 11^2 + 207
AC^2 = 121 + 207
AC^2 = 328
AC = 18.1 cm
