Answer
13.3
Work Step by Step
We first find the surface area if there was no slice, and then we multiply by the portion of the area that is actually there. Recall, there are 2.52 inches in 6.4 centimeters.
$ A = (\frac{240}{360}\pi (2.52^2) = 13.3$
(Note, 2.52 is a long decimal that must be stored in the calculator to get the right answer.)