The mathematics tag has no wiki summary.
11
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2answers
473 views
Origins of איל משולש and Vilna Ga'on's bathroom math
There is a well-known fact that the Vilna Ga'on studied math while in the bathroom since Torah was out of the question in an unclean place. It is also somewhat well-known that he produced the material ...
8
votes
4answers
475 views
High School Math in the Talmud
I'm currently tutoring someone in math that has an atitude of "what's the point of all this... why would I ever need this..." (which is typical of many high-schoolers). To try to pique his interest, I ...
7
votes
2answers
249 views
Magen Avraham - Practically no Plag HaMinḥah or just no Plag HaMinḥah in winter?
Calling all science and math-oriented Judaism.SE-ers!
According to the website MyZmanim.com, today's Halachic times where I work are as follows (only a handful of times are shown because the question ...
6
votes
3answers
271 views
Is the passage describing an approximation of pi or is it one of the miracles of Bais Hamikdash?
In Sepher M'lakhim we read how different measurement was taken. I wonder if this passage (Ⅰ M'lakhim 7:23) is describing an approximation of PI (3.1415...), or was this one of the hidden miracles?
...
6
votes
1answer
211 views
How big does a pentagonal Sukkah have to be?
What is the minimum length requirement for each of the walls of a 5-sided sukkah?
What about 6 sides?
What about 7?
...
What about ∞ sides (i.e. a circle)?
6
votes
1answer
87 views
Aruch Hashulchan's moon-distance estimate
Aruch Hashulchan, Orach Chayim 397:1, says that a מיל is the same as a Russian верста (verst) or 500 сажен (sazhen), which comes to 1066.8 meters. In 426:2, he says the distance to the moon is about ...
5
votes
3answers
219 views
Mathematics in Cheder
I recall reading that their is a pesak/teshuvah/report by a major posek, perhaps an early "later" Acharon, (Rabbi Akiva Eiger zt"l) which noted that at least elementary arithmatic or mathematics was ...
5
votes
1answer
194 views
Do we know anything else about the calculus problem solved by Rabbi Moshe Feinstein?
The biographical sketch of Rabbi Moshe Feinstein that appears in Igrot Moshe volume 8 describes the following (my translation):
The Communist takeover meant the schools taught against religion. ...
4
votes
1answer
103 views
Rambam's method for calculating the conjunction of the moon (and sun)
I think I'm missing something basic here...
The Rambam, in Hilchot Kiddush Hachodesh (6:3) says that the interval between one conjunction to the next is is 29 full days, 12 hours of the 30th day, and ...
4
votes
1answer
95 views
How does this math work out?
The Gemara Eiruvin 56b said that the Migrash (the orange area) is one quarter of the area of the sados (the green area). Let's look at the math. (This is how I understood the maskana)
greenArea = ...
4
votes
1answer
83 views
An improved Jewish calendar after this one expires?
Conventional wisdom has it that about 1600 years ago, the latter Hillel utilized his Sanhedrin to sanctify the Hebrew calendar as we know it today until the year 6000. (Presumably by that point we'll ...
3
votes
1answer
46 views
What does ריש חזית mean?
I'm reading(/trying to read) the introduction to the Vilna Gaon's איל משולש (his geometry textbook). The first two words are ריש חזית.
What does ריש חזית mean?
If it helps, the phrase is immediately ...
2
votes
2answers
116 views
How to calculate 60 days from tekufat tishri for any given year?
I'm trying to pin down an algorithm for calculating when to start saying ותן טל ומטר in diaspora. (In Israel it begins 7 Cheshvan.) I've gotten that we need to know how many centuries passed since ...
2
votes
1answer
45 views
How many calories are in a KeZayith of flour?
I've often wondered how I can be sure I've eaten a KeZayith of flour when I eat something small but complete - like one cookie - and struggle with the decision of whether or not to eat more in order ...
2
votes
0answers
77 views
Mikvah Math for the Sea of Shlomo
In calculating the number of Mikvas that the "Sea of Shlomo" could hold, the Gemara (Eruvin 14b) calculates that it would hold 150. The Gemara asks, that being that the Sea was round, and the ...
1
vote
0answers
99 views
Pidyon HaBen rate
About how many pidyon haben ceremonies are required to be performed per 1000 Jewish births in the past few decades?
The requirements for a pidyon haben are:
Both parents are Israel, not Kohen or ...
