To calculate the percentage of free throws missed by the basketball player, we first determine how many free throws he missed. The player made 5 out of 6 free throws, so the number of missed free throws is:
6 - 5 = 1
Next, we calculate the percentage of free throws missed using the formula:
\[ \text{Percentage missed} = \left( \frac{\text{Number of missed free throws}}{\text{Total number of free throws}} \right) \times 100 \]
Substituting in the numbers:
\[ \text{Percentage missed} = \left( \frac{1}{6} \right) \times 100 \approx 16.67% \]
Thus, he missed approximately 16.67% of his free throws. From the options provided, the closest response is:
16.66¯¯¯¯¯ %.