11 divided by 8.5 == 1.2941 -- however ...

17 divided by 11 == 1.545454

So they are not in proportion.

If the limiting size is 17 for the temporary enlargement, then you need to factor the 8.5 down by 1.1942 -- this means the 8.5 has to be scaled down by 83.7% to get the right ratio, which = 7.11.

So to get the RIGHT ratio to get up to 17 x 22, you need an original page of 7.11" x 11".

DO your math right according to consistent ratios, and you will see what you need to start with.

-- it in fact doubles to 17 x 22. If you calculate this back to 11 x 17, you will see that your original image image needs to be