Question

I need some help please

Answer 1

Dilation:

The dilation factor is the length of image/preimage = 1.5

Thus
Q'R'/QR=1.5
Q'R'=1.5QR = 1.5 (5 cm) = 7.5 cm

(Edited)

Answer 2

So you want to know the length of the segment QR? Here it is:

So first we multiply by 1.5 the side like this: $5*1.5$, we get 7.5, and that is the answer!

Hope this helped! c: