The scale factor of the dilation is [tex]\frac{7}{9}[/tex].
The center of dilation is a point to the right of both circles.
From Analytical Geometry we know that every Circle is defined by its Radius, its form is directly proportional to its radius. Hence, the Scale Factor of the Dilation ([tex]f[/tex]) is the following ratio:
[tex]f = \frac{r_{2}}{r_{1}}[/tex] (1)
Where:
[tex]r_{1}[/tex] - Radius of the original circle.
[tex]r_{2}[/tex] - Radius of the dilated circle.
If we know that [tex]r_{1} = 9[/tex] and [tex]r_{2} = 7[/tex], then the scale factor of the dilation is:
[tex]f = \frac{7}{9}[/tex].
The scale factor of the dilation is [tex]\frac{7}{9}[/tex].
There is a geometrical approach to determine the location of the Center of Dilation. We draw two lines tangent (blue lines) to both circles and we extend to the right of the scene, the point in which both intersects each other is the location of the center of dilation. (representation is included in the image attached below)
In a nutshell, the center of dilation is a point to the right of both circles.
