Find a 3x3 magic square that is composed of 9 prime numbers (not the numbers from 19) and show how you found it.
(A magic square, as you may already know, is one in which the respective sums of the numbers in all the rows, columns, and both major diagonals all add up to the same number.)
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Since "Magic Square" is a term used outside the scope of this problem, I'm sure you can find an answer on the internet. Please find a solution independently.
I didn't know any formula but looking at the square:
A B C
D E F
G H I
and using A+B=G+E=F+I, B+E=G+I etc got to CE=EG etc and came up with the fact that all the lines must be in arithmetic series's. (eg, ABC is in sequence, so is GEC etc). This seems to be true of the example solutions given. Also then the total of each line had to be 3 times the middle number. I would be interested to know how/if this relates to Brian's answer.

Posted by Jils
on 20040310 11:53:25 