To find the scale factor of the dilation, we can compare the coordinates of the points.

The original point is $(4, 6)$ and it maps to $\left(\frac{5}{2}, \frac{15}{4}\right)$.

Scale factor $k$ is given by the ratio of the corresponding coordinates:

• For the x-coordinate: $k = \frac{\frac{5}{2}}{4} = \frac{5}{8}$
• For the y-coordinate: $k = \frac{\frac{15}{4}}{6} = \frac{15}{24} = \frac{5}{8}$

Therefore, the scale factor of the dilation is $\frac{5}{8}$.