BACKGROUND ON THE DAILY DAF
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Eruvin 76
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ERUVIN 76 - dedicated by Dick and Beverly Horowitz and sons Sam and Mike,
in memory of Beverly's mother, Miriam Kurtz.
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*****PEREK #7 CHALON*****
*1*) [line 43] U'SHNAYIM U'MASHEHU MEHEN B'SOCH ASARAH - that is, a bit
more than two Tefachim *besides another four Tefachim* of the
circumference (that is, 6 Tefachim+ of the circumference) is within 10
Tefachim from the ground. (RASHI, see SEFAS EMES)
2) [last line] HEKEFO - its circumference
76b---------------------------------------76b
3) [line 1] RIBU'A - a square
4) [line 2] KAMAH MERUBA YESER AL HA'IGUL? REVI'A! - how much is the
perimeter of a square greater than the circumference of a circle (whose
diameter is the same length as the side of the square)? One fourth (of the
perimeter of the square which is one third of the circumference of the
circle)! (See Insights and Graphic.)
5a) [line 3] IGULA D'NAFIK MIGO RIBU'A - a circle that is inscribed inside
a square
b) [line 4] RIBU'A D'NAFIK MIGO IGULA - a square that is inscribed inside
a circle
6) [line 5] MURSHA D'KARNASA - the projections of the corners
7) [line 6] KOL AMSA B'RIBU'A, AMSA U'TREI CHUMSHEI B'ALACHSONA - for
every Amah along each side of a square the diagonal increases by an one
and two-fifths of an Amah
8) [line 7] SHIVSAR NAKI CHUMSA - 17 less a fifth, i.e. 16 4/5
The diagonal of a square with a side of four Tefachim is 4 X 1 2/5 = 4 8/5
= 5 3/5 Tefachim
The circumference of a circle with a diameter of 5 3/5 Tefachim is 3 X 5
3/5 = 15 9/5 = 16 4/5 Tefachim (using 3 as the rounded value of pi)
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