To determine how much of a circle a 100° angle turns through, you can express it as a fraction of the total circle, which is 360°.
So, the fraction of the circle that a 100° angle represents is:
\[ \frac{100}{360} \]
You can simplify this fraction:
( \frac{100}{360} = \frac{10}{36} = \frac{5}{18} )
Thus, out of the options you provided, the correct answer that represents how much of a circle a 100° angle turns through is:
100/360.