Answer:
4
Explanation:
The scale factor is multiplied by the original figure's dimensions to give the dimensions of the second figure.
To go from 1.5 to 6, you multiply 1.5 by 4, so the scale factor is 4.
Also you can divide a linear dimension of of the image by the corresponding dimension of the original figure to find the scale factor.
6/1.5 = 4
Answer: 4