Answer:
Given that: AB = 12 ft.
From the given figure we have;
diameter = AB = 12 ft.
ft.
Supplementary angles states that the two adjacent angles are sum up to 180 degree.
and
are supplementary angles.
by definition of supplementary angles;

Subtract
from both sides we get;
To find the length of arc AC;
Formula for length(L) of arc is;


substitute the given values; we have;
ft
Therefore, length of arc AC is,
ft