How to calculate the same position on different bitmaps?

Question

I have 2 photos, one has a dimension of 300x300 and the other one is 1200x1200. I drew one text to the position A = (50, 40) in the 300x300 image.

How can I calculate the same position A on the 1200x1200 image?

UPDATE 2:

IF dimension is not round (such as 523 x 412...) - x, y after multiply will be deflected

Answer 1

you may go with relative position calculation as follows.

AAx = (50/300)*1200; 

AAy = (50/300)*1200;

so your new position will be AA = (200,200)