To determine the length of line segment \( AC \), we need additional information about points \( A \) and \( C \). Typically, this information would involve coordinates or distances between points.
If we have coordinates (for example, \( A(x_1, y_1) \) and \( C(x_2, y_2) \)), we can use the distance formula:
\[ AC = \sqrt{(x_2 - x_1)^2 + (y_2 - y_1)^2} \]
Please provide the coordinates or the context within which these points exist, and I will be able to help calculate the length of \( AC \).