Recall that a dilation with center (0, 0) and scale factor [tex]k[/tex] maps [tex](x,y)[/tex] onto [tex](kx, ky)[/tex].
Now, triangle ADE is formed by
[tex]A=(0,0),\quad D=(0,2),\quad E=(4,0)[/tex]
Whereas triangle ABC is formed by
[tex]A=(0,0),\quad B=(0,4),\quad C=(8,0)[/tex]
In other words, the coordinates of B and C can be obtained by multiplying by 2 the coordinates of D and E.
This means that you get ABC from ADE by dilating with center (0,0) and scale factor 2.
