Line segment QR is dilated to create line segment Q'R' using the dilation rule DT,1.5. Point T is the center of dilation. Line segment Q R is dilated to create line segment Q prime R prime. The length of R T is 6 and the length of R prime R is y. What is y, the distance between points R and R'? 3 units 4 units 6 units 9 units