No regulation that I am aware of. It is normally put out by the Commander in a policy memo.
AFI 36-2903 : 1.2.13. Authorized headgear will be worn while outdoors unless in an area designated as a ―no hat area by the installation commander or equivalent. Headgear will also be worn indoors by armed Security Forces personnel or others bearing arms while performing duties.
It depends on how you define "proper", in this case. Situation dictates. No regulation from any branch (that I've found) requires you to salute a stationary flag as you pass it by yourself. I doubt you'll catch much flak for doing so, however, as it's still a sign of respect. Extra salutes are rarely penalized, unless you salute a living enlisted service member (saluting them disrespects the officers to whom the salute is actually owed), and even then it's usually a very light reprimand. Cased flags are not saluted. This includes folded flags. Small flags carried individually (like cheap parade flags) are not saluted. Flags inappropriately displayed (as clothing, etc.) are not saluted - though you may want to inform anyone who displays them that way of the disrespect they are inadvertently showing the flag. If it is being raised or lowered, salute. If it passes by you in a color guard, salute. If Colors, Reveille, TAPS, or the National Anthem is being played, salute. If you are leading a formation, salute within 6-30 paces, and cut the salute when you are 6 paces past it. If you are passing in review, you may be told to command your formation to do the same, depending on your area of service. If in ceremony, the ceremony will dictate when you salute the flag. If you are in a formation, you do not salute until commanded (or in an open ranks inspection, in which case you salute your inspector when outdoors). Most services do not have you salute when you are not wearing a cover (hat), unless out of uniform, and then you give the civilian salute (hand over heart). You can, per the new regulation, give a military hand salute out of uniform now if you wish, but you may get asked about it. Rifle salutes follow the same procedure. You'll always be told when a gun salute is appropriate. Finally, just remember this, especially when it comes to the American flag: When in doubt, salute. You'll rarely get in any trouble for saluting at the wrong time (and if you do it will only be a verbal reprimand), but you WILL get in trouble for failing to salute at the right time (Up to and including being penalized for violating UCMJ Article 89, if you're military).
it is helpful to determining a cirlcle
There is no regulation that requires them. But some sort of speed regulation is helpful, particularly if there are children in the area.
Yes
?
Yes
Yes
Yes
Determining the area of a rectangle is simply multiplying its length by its width.
A surface area would be vital for determining volume
8100 ft2