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The construction of Solomon's temple includes a piece of furnishing described in 1 Kings 7:23 (ESV):

Then he made the sea of cast metal. It was round, ten cubits from brim to brim, and five cubits high, and a line of thirty cubits measured its circumference.

So if the diameter = 10 cubits and the circumference = 30 cubits, then π = 3 by the equation C = π * D.

Of course, such an object does not exist since π = 3.14159... yet clearly the sea was constructed at some point. So how do we resolve this contradiction?

  • Considering the range of widely spread explanations, and how some non-obvious and counterintuitive explanations are repeated over and over again, I think this is a very good question. – dancek Nov 12 '11 at 14:38
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    If it's good enough for the Indiana legislature it's good enough for me! – Affable Geek Mar 16 '12 at 13:27
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    ...maybe I should come here more often if no one noticed and fixed the "3.141 4 9..." error for five months! -_- – El'endia Starman May 4 '12 at 4:14
  • @El'endia Starman: Weird. I guess I typed it from "memory" rather than copy-n-paste. Thanks. (Or maybe it was a clever ploy to prove that exactitude is over-rated. Yeah, that's it!) – Jon Ericson May 4 '12 at 4:31
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    I believe Petr Beckmann's book, "The History of Pi", cites this particular Scripture. – user15733 Aug 27 '16 at 12:19
70
+500

It's hard to get inside the minds of people from other cultures, especially when we are separated by time as well as distance. And the main problem here is cultural: We have an expectation of greater precision than ancient people did. The other answers hint at this, but IMO they don't fully appreciate the divide between modern and ancient levels of precision.

There are several reasons we can't use the measurements in 1 Kings 7:23 to calculate pi:

  • The other answers are on the right track regarding rounding. At the time the Tanakh was written, the decimal point had not been invented. So if the diameter were 9.55 cubits, there would simply be no way to record that except to round to the nearest cubit. This, however, does not prove the diameter was 9.55 cubits. We just can't know with any greater precision.

But there's more reasons for uncertainty:

  • A cubit was not a uniform standard of distance. It was about the length of the forearm, from the elbow to the tip of the middle finger or from the elbow to the base of the hand. Moreover, arm length varies from person to person. How can we know whether the "line of 30 cubits" measuring the circumference uses the same cubit as the 10-cubit measurement across?
  • Can we say for certain that the line of 30 cubits fit perfectly around the circumference with both ends touching and no overlap? The ESV translation above doesn't necessarily lead to that implication, though some others do.

Also note:

  • Unlike passages that are meant to be instructional (e.g., Exodus 26:1-6), where specificity is relatively important, this one is merely descriptive. It doesn't need to be consulted by workers attempting to build the object according to spec. The object already existed.
  • This passage is not a word problem from an early geometry textbook, where the reader's job is to calculate the value of pi. Its purpose is to describe an object in the temple. For that purpose, the round numbers "10 cubits" and "30 cubits" would give most people of the time a good idea of its size.

In conclusion:

There are many factors weighing against using the numbers in this passage as a precise mathematical equation. Our desire for decimal point accuracy misses the point of the Scripture, and says more about the modern world than it does about God.

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    +1 for the conclusion alone. Pointing out the difference in genre between what was written and how some people try read it is also very appropriate. – Jon Ericson Nov 17 '11 at 23:50
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    For some more information about how pi was estimated in ancient times, see this article. The Egyptians apparently used an estimate of 22/7 (which I learned in grade school myself). Details of how they might have applied the knowledge to building pyramids can be found here. Of course, there are lots of strange theories about how the Egyptians might have learned to build the pyramids and most of them are bunk. ;-) – Jon Ericson Nov 18 '11 at 18:23
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Many different explanations have been proposed. The best article I've read on the subject is The Number Pi in the Bible by Abarim Publications.

I'll begin with what I think is the obvious and correct explanation, then mention some other explanations (mentioned e.g. in the article above).

10 ≠ 10.0 (rather, "10" means (10.0 ± 0.5))

1 Kings 7:23 says nothing about the value of pi. It just mentions two values:

  • a diameter of "10 cubits"
  • a circumference of "30 cubits"

Now, imagine that the diameter was actually 9.55 cubits. The author would still probably have written "10 cubits" instead of going for the exact measure. You shouldn't be surprised that

30.0 / 9.55 = 3.1413…

Which is quite near pi. Of course, "30" isn't exact either. Anyway, it's clear that for x/y = pi, we can have x ≈ 30 and y ≈ 10. We can also calculate the possible range for pi:

x ∈ [29.5, 30.5[
y ∈ [9.5, 10.5[
pi = x/y ∈ ]2.80…, 3.21…[

Other explanations

There are many other explanations, which are in my opinion more complicated than the obvious one. Some of these might be true, but we don't need to assume so. Credits for much of the list goes to the article The Number Pi in the Bible.

  • The rim of the sea was of a finite width. The diameter was measured on the outside, and the circumference on the inside.
  • The top of the rim protrudes outside. The circumference is measured from the lower part while the diameter is measured from the top.
  • The sea was actually oval-shaped, not circular.
  • The verse includes a coded message in Hebrew, and by calculating numerical values and using some math we arrive at pi = 3 * 111/106 = 3.1415….
  • A range of unscientific explanations, such as...
    • The Bible isn't a science textbook, so this is no problem!
    • It's a miracle. The measurements are physically not possible, but God is above physics.
    • Actually pi = 3 as revealed by God, and we should adapt our man-made scientific ideas accordingly.
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    That's a lovely rabbit hole you made me jump down. ;-) The article mentions that to an engineer, π ≈ 3, which is a pretty good summary. – Jon Ericson Nov 14 '11 at 23:07
  • By using the concept of Significant Figures, the math is correct. Heh... I guess, for that matter, whoever said the thing was a perfect circle anyway. "Round" is descriptive, not mathematical. – user6152 Nov 23 '14 at 3:54
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To start with, compare the circle the diameter we're given would make with the circle the circumference we're given would make:

Since a circumference is π times the diameter, a 'pure' circle of 10 cubits in diameter as we describe the sea as having would be 10π cubits in circumference, or roughly 31.4 cubits.

Now, since the circumference attributed to our sea is only 30 cubits, it represents a smaller circle, which is 30/π or roughly 9.55 cubits in diameter.

Or to tabulate it:

Circle A:  ~9.55 cubits diameter,  30   cubits circumference
Circle B:  10    cubits diameter, ~31.4 cubits circumference

Given that, we have two diameters differing by about .45 cubits (about eight inches on an 18-inch cubit--a sizable difference).

Since we know the sea was a physical object and not a circle bounded by an infinitesimal line, we can safely understand that the sea must be of some thickness; on this ground, it would not be unreasonable to take the shorter dimension as the inner measurement, and the longer dimension as the outer measurement, and see where that takes us.

Dividing the difference in the diameters in half, this would make the wall around our sea at least .225 cubits thick--i.e., about four inches on either end of the sea, assuming an eighteen-inch cubit.

Do we have any authority for assuming that this is the case and saying the sea was anything like four inches thick?

A couple of verses after this we have 1 Kings 7:26, which gives it to us outright:

Its thickness was a handbreadth, and its brim was made like the brim of a cup, like the flower of a lily. It held two thousand baths.

A handbreadth as a unit of measurement is generally given as between three and four inches.

(The 'Number Pi in the Bible' site linked elsewhere gives as its rebuttal to this sort of argument the statement "The writer makes sure that no question remains: both the diameter and the circumference are taken over-all." - though I'm not sure on what basis he sees that.)

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    Welcome to Biblical Hermeneutics! This is a well-reasoned response. I too wonder why this explanation was so quickly dismissed in that article. – Jon Ericson Nov 17 '11 at 6:28
  • @MukeTever I don't understand what you're saying. If the circumference were 30 and the real diameter 9.55, then measuring the diameter on the inside of a .225-thick wall would yield 9.10. Can you clarify? – dancek Nov 18 '11 at 10:58
  • I'm starting to assume this is the brim-protruding-outside argument, which I think is the most believable one of those assuming exact values of 30.0 and 10.0. It's just worded in a way that I have a hard time understanding (ESL, sorry). – dancek Nov 18 '11 at 11:03
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    @Dancek The same argument could be used for a protruding brim; I just had in mind the thickness of the sea itself. The argument is probably the same for any shape that takes into account the thickness as well as the circumference and diameter given. – Muke Tever Nov 18 '11 at 14:01
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    (+1) This seems like the best answer to me. The diameter would be useful information if you wanted to fit the bowl through a door or something. The circumference would be more useful in referencing how much water it could hold. So, it seems reasonable to reference both, slightly different measurements in the way they were referenced. – Jas 3.1 Jul 14 '12 at 0:42
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we don't even know what the real numerical value of pi is. When written out as a number, it will always be rounded. The question is: At which decimal place will you believe God's Word is true? The hundredth decimal place, the thousandth decimal place? I'm guessing for most, there will never be enough decimal places. For me pi = 3 is close enough.

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    +1 for a common-sense answer though you haven't really added much that hasn't been said already ;) – Jack Douglas Jan 11 '13 at 14:45
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From a post by Cecil Adams, aka The Straight Dope

In 150 A.D. a Hebrew rabbi and scholar named Nehemiah attempted to explain away the anomaly in Chronicles by saying that the diameter of the tub was 10 cubits from outer rim to outer rim, whereas the 30 cubit circumference was measured around the inner rim. In other words, the difference between the biblical notion of pi and the actual value may be accounted for by the width of the tub's walls. How's that for tap dancing, eh?

3

Let us take a look at all the measures (of time, length, surface, and volume) involved in 1 Kings 6-7, describing the construction of Solomon's Temple :


1 Kings 6:1  In the four hundred and eightieth1 year after (the Exodus), in the fourth year of Solomon, in the second month.

1 The Septuagint has four hundred and fortieth.

1 Kings 6:2  The length thereof was threescore cubits, and the breadth thereof twenty cubits, and the height thereof thirty cubits.

1 Kings 6:3  Twenty cubits was the length thereof; and ten cubits was the breadth thereof.

1 Kings 6:6  The nethermost chamber was five cubits broad, and the middle was six cubits broad, and the third was seven cubits broad.

1 Kings 6:10  Chambers, five cubits high.

1 Kings 6:16  He built twenty cubits on the sides of the house.

1 Kings 6:17  The house, that is, the temple before it, was forty cubits long.

1 Kings 6:20  Twenty cubits in length, and twenty cubits in breadth, and twenty cubits in the height thereof.

1 Kings 6:23  Two cherubims of olive tree, each ten cubits high.

1 Kings 6:24  Five cubits was the one wing of the cherub, and five cubits the other wing of the cherub: from the uttermost part of the one wing unto the uttermost part of the other were ten cubits.

1 Kings 6:25  The other cherub was ten cubits.

1 Kings 6:26  The height of the one cherub was ten cubits, and so was it of the other cherub.

1 Kings 6:31  Doors of olive tree: the lintel and side posts were a fifth part of the wall.

1 Kings 6:33  The door of the temple posts of olive tree, a fourth part of the wall.

1 Kings 6:37  In the fourth year, in the (second) month.

1 Kings 6:38  In the eleventh year, in the eighth month, was the house finished. So was he seven years in building it.


1 Kings 7:1  Solomon was building his own house thirteen years.

1 Kings 7:2  The length thereof was an hundred cubits, and the breadth thereof fifty cubits, and the height thereof thirty cubits.

1 Kings 7:6  The length thereof was fifty cubits, and the breadth thereof thirty cubits.

1 Kings 7:10  Stones of ten cubits, and stones of eight cubits.

1 Kings 7:15  Two pillars of brass, of eighteen cubits high apiece: and a line of twelve cubits did compass either of them about.

1 Kings 7:19  The chapiters that were upon the top of the pillars, four cubits.

1 Kings 7:23  Ten cubits from the one brim to the other: his height was five cubits: and a line of thirty cubits did compass it round about.

1 Kings 7:26  It was an hand breadth thick: it contained two thousand baths.

1 Kings 7:27  Four cubits was the length of one base, and four cubits the breadth thereof, and three cubits the height of it.

1 Kings 7:31  The mouth of it within the chapiter and above was a cubit: but the mouth thereof was round after the work of the base, a cubit and an half.

1 Kings 7:32  The height of a wheel was a cubit and half a cubit.

1 Kings 7:35  In the top of the base was there a round compass of half a cubit high.

1 Kings 7:38  One laver contained forty baths: and every laver was four cubits.


We notice that :

  • all numbers above twenty are exact multiples of ten.

  • fractional parts are mentioned only when the integral part is smaller than two.

An expression of the form thirty-one and a half cubits makes therefore little sense within the given context.


The above observations still hold, even if we were to take all numeric expressions (not necessarily related to measure) from the aforementioned two chapters into account, with the small caveat that the first would have to be amended to read exact multiples of five.

  • Similarly, the Jubilee year yields a rational approximation for the square root of 2 as being about 10 / 7. – Lucian Oct 11 '17 at 11:40
  • what's a specific reference for this √2 approximation? – Ray Butterworth Oct 7 at 13:45
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The Septuagint version of 1 Kings gets it right with a diameter of 10 cubits (interior diameter) and a circumference of 33 cubits (exterior circumference). Divide 33 by 3 1/7 and you get exactly 10 1/2 cubits for the exterior diameter.

0

The obvious answer is that the bible is correct.

The number to use in physics and engineering calculations depends on how much precision you need.

For very rough calculations, it is common to use a fermi approximation, where:

π = 1

When making an "in your head" calculations approximation in Physics, one will use:

π = 3

And when using a calculator or computer, it is common use the really long version of π, that contains too many decimal places to list here. Please notice that 3.14 or 3.14159 would never be used in a serious scientific calculation; this approximation isn't that useful.

It is worth noting that the Bible was written before the development of Arabic numerals around 700 C.E., and long before the development of decimals in the 1500s. And modern calculators weren't around until the 1980s.

  • This, like the previously accepted answer, is completely wrong from the standpoint of the history of science. You do not need a decimal point, or Arabic numerals, to express the value of pi to a high degree of accuracy. The Babylonians had sexagesimal fractions, and Archimedes expressed the value of pi very exactly with ordinary fractions using Greek numerals. – fdb Aug 27 '16 at 19:03
  • @fdb You missed the point. I too am capable of computing pi with a high degree of accuracy. But I use pi = 3 in my day to day life. – axsvl77 Aug 28 '16 at 22:40
  • So why did you mention "Arabic numerals" and "decimals"? – fdb Aug 28 '16 at 22:41

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