Answer:
The value of RD' is 5 units.
Step-by-step explanation:
It is given that rectangle ABCD was dilated to create rectangle A'B'C'D' using point R as the center of dilation.
The scale factor is the proportion of side length of image and side length of preimage.
\(k=\frac{\text{lenght of image}}{\text{lenght of preimage}}\)
\(k=\frac{B'C'}{BC}\)
\(k=\frac{4}{12}\)
\(k=\frac{1}{3}\)
Scale factor is also defined as
\(k=\frac{RD'}{RD}\)
\(\frac{1}{3}=\frac{RD'}{15}\)
Multiply both sides by 15.
\(RD'=5\)
Therefore the value of RD' is 5 units.
