To find the scale factor Leo used, we can calculate it by dividing the length of the sides in the enlarged photograph by the length of the sides in the original design.
The original side length is 3 cm, and the enlarged side length is 8 cm. Therefore, the scale factor is calculated as follows:
\[ \text{Scale Factor} = \frac{\text{Enlarged Length}}{\text{Original Length}} = \frac{8 , \text{cm}}{3 , \text{cm}} = \frac{8}{3} \]
Thus, the scale factor Leo used is \(\frac{8}{3}\).
From the provided options, the closest correct response is:
223
2 Start Fraction 2 over 3 End Fraction
(Note: The correct scale factor is \(\frac{8}{3}\), but it seems that option formatting caused confusion. If you meant "2" to represent the "larger" side of a fraction, that is not the case in this calculation, and we have confirmed that the calculated scale factor is \(\frac{8}{3}\).)