To find the length of each piece when a 6-foot rope is cut into 9 pieces, you would divide the total length of the rope by the number of pieces.
So, the calculation would be:
\[ \frac{6 \text{ ft}}{9} = \frac{2}{3} \text{ ft} \]
Each piece is \( \frac{2}{3} \) ft long.
Therefore, you can fill in the blank as follows:
"There are 9 pieces that are \( \frac{2}{3} \) ft long."