We are given coordiates of vertices of triangle ΔHJK as H(8,8), J(8,4), K(4,4)
and coordinates of transformed triangle ΔH’J’K are H'(2,2), J'(2,1), k'(1,1).
We can clealry see that if we divide each value in coordinate by 4, we get the coordinates of the transformed triangle.
Let's see, what's dilation being applied there : H(8,8) ---> 1/4 (8,8) = H' (2,2) ,
J(8,4) ---> 1/4(8,4) = J'(2,1) and
K(4,1) ---> 1/4 (4,4) = K'(1,1).
So, we can clearly see that each coordinate is being multiplied by 1/4.
So, we can say the scale factor of dilation is 1 over 4, that is 1/4.
, where 
is circumference and tex]d[/tex] is the diameter. They are related by a constant 
(pi).