# How long until “final totality”? [closed]

It is given that the angular size of the Sun as viewed from Earth is $0.533^\circ$, the distance of the Moon from Earth at perigee is $3.633\times 10^5$ km, and the mean radius of the Moon is $1737.1$ km.

Suppose that the perigee of the Moon is receding from Earth at a uniform rate of $4$ cm/year. Estimate how long it will take to reach "final totality" (i.e. when we can no longer observe total solar eclipse on Earth).

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I'm going to migrate this question to the physics.SE site. There will be a link that appears below the question here that you can follow to the new location of your question. If you need help associating your account to one on physics.SE, you can flag your question for moderator attention, and someone over there will help out. –  Zev Chonoles Nov 28 '11 at 5:09
The initial question is really a math question (after I looked up what "perigee" is). –  Jonas Meyer Nov 28 '11 at 5:11
Hi jason, and welcome to Physics Stack Exchange! As our FAQ says, we don't allow "do my homework"-type questions here. What that means is that you'll need to edit your question to show your work and ask about the specific physical concept that is confusing you. You can find more information on our homework question policy on meta. –  David Z Nov 28 '11 at 5:27
Physics.se it seems, more and more is wieved as a dump for silly/elementary/nonsense questions from other branches. This questiion is math, obviously, but math.se expelles such elementary questions. So, why not "sending" back? –  Georg Nov 28 '11 at 11:13
You say that as if math isn't dumped on either, buddy... ;) –  user172 Nov 28 '11 at 12:47