Question

Rectangle ABCD was dilated to create rectangle A'B'C'D' using point R as the center of dilation.

If RD = 15, what is RD'?

3 units
5 units
6 units
9 units

Answer 1

The value of RD' is 5 units.

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=(B'C')/(BC)`

`k=(4)/(12)`

`k=(1)/(3)`

Scale factor is also defined as

`k=(RD')/(RD)`

`(1)/(3)=(RD')/(15)`

Multiply both sides by 15.

`RD'=5`

Therefore the value of RD' is 5 units.

Answer 2

5

Explanation: