Answer: a) 1080 degrees.
Step-by-step explanation: Total sum of interior angles = (n - 2) * 180 degrees,
where n is the number of sides of the polygon.
In this case, the shape has 8 sides, so substituting n = 8 into the formula:
Total sum of interior angles = (8 - 2) * 180 degrees = 6 * 180 degrees = 1080 degrees.
Therefore, the correct answer is:
a) 1080 degrees.