To solve for XY we will set up a proportion. Lets do it:- Den solve:-

Now lets solve for x:-
Cross multiply;-
16.5 × 8.5 = 140.25
Divide:-
140.25 ÷ 17 = x
140.25 ÷ 17 = 8.25
x = 8.25
CHECK OUR WORK:-
16.5 × 8.5 = 140.25
17 × 8.25 = 140.25
We were RIGHT!!
So,
x = 8.25. (In your pic XY = 8.25)Hope I helped ya!!!