The question is often raised whether or not the Bible (specifically 1st Kings 7:23-26, and 2nd Chronicles 4:2-5) endorses a value of 3.0 for pi (circumference=30/diameter=10) as opposed to the "correct" value of 3.14159... . Here are the Bible verses under consideration, along with some variant sources, and additional supporting context:
2 Chronicles 4:2-5 NIV
(Hebrew)
(LXX):
2 He made the Sea of cast metal,
circular in shape,
measuring ten cubits from rim to rim and five cubits high.
It took a line of thirty cubits to measure around it.
3 Below the rim,
figures of bulls encircled it - ten to a cubit.
The bulls were cast in two rows in one piece with the Sea.
4The Sea stood on twelve bulls,
three facing north, three facing west,
three facing south and three facing east.
The Sea rested on top of them,
and their hindquarters were toward the center.
5 It was a handbreadth in thickness,
and its rim was like the rim of a cup,
like a lily blossom.
It held three thousand baths (3000 "measures" in this LXX translation).
Josephus'
Antiquities (8:3:5):
5. Solomon also cast a brazen sea,
whose figure was that of a hemisphere.
This brazen vessel was called a sea for its largeness,
for the laver was ten feet in diameter,
and cast of the thickness of a palm.
Its middle part rested on a short pillar that had ten spirals round it,
and that pillar was ten cubits in diameter.
There stood round about it twelve oxen,
that looked to the four winds of heaven,
three to each wind, having their hinder parts depressed,
that so the hemispherical vessel might rest upon them,
which itself was also depressed round about inwardly.
Now this sea contained three thousand baths.
(The Dead Sea Scrolls do not contain any relevant information.)
My own take is that the Biblical author was simply describing the structure which had been made, using the measuring tools which were then available; but many differing opions have been expressed: this link provides some Internet Speculation about the "Biblical" π:
Here I will quote what I believe to be one of the better answers from that link, one which I consider to be a reasonable answer to the question:
begin quote:
...
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). [this link has been cropped above, but can it still be followed below]
1 Kings 7:23 says nothing about the value of pi. It just mentions two values:
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...[
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.
pi = 3 * 111/106 = 3.1415....pi = 3 as revealed by God, and we should adapt our man-made scientific ideas accordingly.Here it is probably worth noting that, although the Bible isn't exactly a "science textbook," we should still expect its information to be scientifically and mathematically correct (at least within the limits of the cultures and languages in which it has been recorded). However, this must also be balanced by adequate caution, considering the antiquity of the text, and the expected difficulty encountered in hand-copying ancient records, century after century.
The variations in the numbers and units provided in the different sources cited above warn us of what kind of copying errors the text might have sustained, back before reliable archival systems were developed. We can identify some additional warnings by doing a little bit of math:
Biblical Weights and Measures 18 inches/cubit, 5.8 gallons/bath (or 8.7 gallons/bath)
And a gallon is 231 cubic inches ...
So, a cubic cubit would be: 18×18×18 = 1728 cubic inches; 1728/231 = 7.48 gallons; and 7.48/5.8 = 1.29 baths. It follows that even the smaller "2000 baths" would be: 2000/1.29 = 1550 cubic cubits, which is several times more than would fit in even a rectangular space of 10×10×5 = 500 cubic cubits! (Using 3000 baths, or 8.7 gallons/bath, would only increase the volume of the water.)
This provides additional evidence for what was already obvious to us, from the variations between the different copies: Hand-copied documents often contain copying errors. This is especially true of numbers, or of mathematical relationships, for which mistakes are less obvious to uncritical readers.
Again, my own understanding is that the Biblical author was merely describing what had been made, using the tools that were then available, (and that many very hard working scribes, over the centuries, had only limited success making accurate copies.) No claim was ever made that the numbers were (or are) to be understood as exact reflections of a conceptually perfect circle.
These two verses would only become a problem to me if someone were to accuse me of "heresy" for believing (or possibly even teaching) what I know to be the true value of pi, for conceptually perfect circles, ... or even for suggesting (as I am going to do, here and now) that the "correct-original" volume of the "sea" may have been "300 baths."
Let's do the math:
Volume of a hemisphere: 2/3πR³ = 261.8 cubic-cubits (R= 5-cubit Radius)
... × 1.29 baths/cubic-cubit = 337.7 baths.
That's if it's filled right up to the lip; 300 baths leaves about 1/3 cubit of slosh margin.
(Or, the original author might have rounded the number to reflect uncertainty.)
Either way, at some point in ancient time, preceeding and impacting every single one of the sources quoted above, this volume of water appears to have been subjected to a simple decimal-point error.