The rule for dilation (scale factor k) about the origin is given by:
(x,y)->(kx,ky)
The scale factor k is therefore obtained by dividing the corresponding coordinates of the image by those of the preimage, namely
scale factor = k = [tex]\frac{OS'}{OS}=\frac{OT'}{OT}=\frac{PV'}{OV}[/tex]
where O is the origin (0,0)
