executive 7,5×10"

letter 8,5×11"

Hints for North American paper users
The United States, Canada, and in part Mexico, are today the only industrialized nations in which the ISO standard paper sizes are not yet widely used. In U.S. office applications, the paper formats "Letter" (216 × 279 mm), "Legal" (216 × 356 mm), "Executive" (190 × 254 mm), and "Ledger/Tabloid" (279 × 432 mm) are widely used today. There exists also an American National Standard ANSI/ASME Y14.1 for technical drawing paper sizes A (216 × 279 mm), B (279 × 432 mm), C (432 × 559 mm), D (559 × 864 mm), E (864 × 1118 mm), and there are many other unsystematic formats for various applications in use. The "Letter", "Legal", "Tabloid", and other formats (although not these names) are defined in the American National Standard ANSI X3.151-1987.
http://www.cl.cam.ac.uk/~mgk25/iso-paper.html

United States Paper Sizes in Inches

Name Size
Executive 7.5 x 10
A (letter) 8 1/2 x 11
Legal 8.5 x 14
B (ledger) 11 x 17
Super A3/B 13 x 19
C 17 x 22
D 22 x 34
E 34 x 44
F 28 x 40
G 11 x (22 1/2 to 90)
H 28 x (44 to 143)
H 28 x (44 to 143)
J 34 x (55 to 176)
K 40 x (55 to 143)
http://www.inkjetart.com/weight.html