Since the units are incompatible, we can't convert in into in². Inches measures length while inches squared measures area.
Yes, Alaska has more than ten inches of precipitation. Depending on location in Alaska the preciptiation varies. Anchorage 16.08 inches, Barrow 4.16 inches, Bethel 16.18 inches, Fairbanks 10.34 inches, Homer 25.45 inches, Juneau 58.33 inches, Kodiak 75.35 inches, Nome 16.56 inches, Valdez 67.41 inches. Alaska annual precipitation average is 22.70 inches.
Cubic inches measures volume. Square inches measures area. Therefore, you can not compare the two. It is like comparing feet and cups.
A standard poster measures 24 inches by 36 inches, a mini poster measures 11 inches by 14 inches or 16 by 20 inches. Giant posters measure 40 inches by 60 inches.
The length of a box that measures 18 cm is approximately 7.1 inches.