A4 and Letter: equal viewer width is not equal paper size

mixed-sizes.pdf has an A4 page, approximately 595.28×841.89 pt, and a Letter page, 612×792 pt. Place main-two.pdf before it for a four-page merge.

1. Record source counts and dimensions; merge main-two.pdf followed by mixed-sizes.pdf.

2. Download merged.pdf and check A1, A2, A4, LETTER in that order.

3. Inspect dimensions of pages 3 and 4 in a reader that exposes individual page sizes. Fit-to-width display is insufficient evidence.

Require 2+2=4 pages. The first three are approximately A4 and the fourth remains Letter. This task permits mixed dimensions; the result is neither a merge failure nor a conversion of every page to A4.

If all-A4 delivery is mandatory, reject this output. Re-layout or re-export using explicit scale and margin rules, then inspect text and stamps again. This exercise does not verify physical printing.
