The scale factor of a dilation, denoted as k, is the ratio of the length of a line segment in the image to the corresponding line segment in the original figure.
Given that the point of dilation is the origin, we can calculate the scale factor k by dividing the coordinates of the image point A'(-10, -15) by the corresponding coordinates of the original point A(-2, -3).
So, for the x-coordinates: k = -10 / -2 = 5 And for the y-coordinates: k = -15 / -3 = 5
Therefore, the scale factor k of the dilation is 5.