Answer:
sf = 0.2
Explanation:
You can calculate a scale factor the same way you calculate if a table is proportional but flipped by using the equation for the constant of proportionality but flipped (x/y) in this equation y is almost always bigger than x and so in this case 2.5 would be y and 0.5 would be equal to x so. 0.5 / 2.5 = 0.2
The person above is incorrect please do not type 5. You will get this question wrong if you do.
Hope this helped o_o