To find the scale factor used to create the travel version of the triangular piece, we can use the formula for scale factor:
\[ \text{Scale Factor} = \frac{\text{New Size}}{\text{Original Size}} \]
In this case, the original size is 3 inches, and the new size (travel version) is 0.5 inches. Plugging the values into the formula gives us:
\[ \text{Scale Factor} = \frac{0.5}{3} = \frac{1}{6} \]
Therefore, the scale factor used to create the travel version of the piece is \( \frac{1}{6} \).
The correct response is: 1/6.