To find the scale factor Leo used to enlarge the original pentagon from 3 cm sides to 8 cm sides, we can use the formula for the scale factor:
\[ \text{Scale Factor} = \frac{\text{New Size}}{\text{Original Size}} \]
In this case, the new size is 8 cm (the size of the enlarged pentagon) and the original size is 3 cm (the size of the original pentagon). Plugging in these values, we get:
\[ \text{Scale Factor} = \frac{8 \text{ cm}}{3 \text{ cm}} = \frac{8}{3} \]
To convert this fraction into a mixed number, we divide 8 by 3:
\[ 8 \div 3 = 2 \quad \text{remainder} \quad 2 \]
This gives us:
\[ \frac{8}{3} = 2 \frac{2}{3} \]
Thus, the scale factor Leo used to create the photograph is \(2 \frac{2}{3}\).
So the correct answer is:
c. 2 2/3