Remember that the scale factor is the ratio of the length of a side of one figure to the length of the corresponding side of the other figure.
In this problem, we've got a table with two measures for the sculpture and the model.
As you can see, there's a ratio between each measure:
[tex]\frac{21}{6}=\frac{14}{4}=\frac{28}{8}=3.5[/tex]
This means that the sculpture is 3.5 times bigger than the model.
Therefore, as a fraction, the scale factor is 7/2.
