The sum of the interior angles of a polygon can be found using the formula: (n-2) x 180 degrees, where "n" represents the number of sides of the polygon.
In this case, the polygon is a pentagon, which has five sides. Substituting "n" with 5, we get:
(5-2) x 180 degrees = 3 x 180 degrees = 540 degrees.
Therefore, the sum of the interior angles of a pentagon is 540 degrees. Hence, the correct option is 540\(^o\).