Rectangle ABCD was dilated to create rectangle A'B'C'D' using point R as the center of dilation. Point R is the center of dilation. Rectangle A B C D is dilated to create smaller rectangle A prime B prime C prime D prime. The length of side A prime B prime is 3 and the length of side B prime C prime is 4. The length of side A B is 9 and the length of side B C is 12. If RD = 15, what is RD'? 3 units 5 units 6 units 9 units