help with geometry question

Question

in the diagram below, RV is the image of SU after a dilation centered at point T. Which of the following ratios could be used to calculate the dilation factor

a) TS/SR

b) VR/US

c)VU/UT

d) TU/TV

Answer 1

If RV is the image of SU after a dilation by a factor of k, then RV = k·SU. Hence RV/SU = k. The general rule is that the ratio of corresponding sides (image to object) equals the dilation factor. So in your case RV/SU = k. That ratio is given in your choices but the corresponding sides are each listed backwards.