Scale down a SpriteRenderer whilst keeping it's aspect ratio in script?

I'm trying to scale a sprite down to a particular set size so all other different res sprites follow suit.

Not sure how to tackle it... if anyone knows or have any links or clues please let me know, thanks.

 

i'm far from an expert but i guess you could try deviding rather than subtracting.
say you want the scale the Y from 5 to 2 but your X is 8, try the following (not actual script)

set X to (X / (Y (5) / targertY (2)) (=3.2)
set Y to targetY (2)

it's important though that you get your original X and Y before atempting to scale them.
also i haven't checked my math, might want to change something in the calculations