To represent thirteen-eighths (which can be written as \( \frac{13}{8} \)) using a circle, Jason should divide the circle into eighths since the denominator is 8.
As \( \frac{13}{8} \) is an improper fraction, it means it represents one whole (which is 8/8) plus an additional \( \frac{5}{8} \) (because \( 13 - 8 = 5 \)).
By dividing the circle into 8 equal parts (eighths), he can then represent \( \frac{13}{8} \) with one whole circle (8 parts) and an additional 5 parts from a second full circle, totaling 13 parts in this context.
Thus, Jason should divide the circle into 8 equal parts.