Point D is the center of dilation. Line segment S U is dilated to created line segment S prime U prime. The length of Q S is 4 and the length of Q U is 5. The length of S S prime is 4 and the length of U U prime is 5.
Line segment SU is dilated to create S'U' using point Q as the center of dilation.
The scale factor of the dilation is
.