



 
Hi Priscilla, Assuming you mean a regular octagon I drew a diagram. If you start at P and go counterclockwise around the regular octagon until you are $\frac{17}{20}$ of the way around then, $\frac{17}{20} \times 8 = 6.8,$ so you are at $Q$ which is on the side numbered 7. I hope this helps,  


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