Book:Tablet/YBC 7289
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Tablet YBC $7289$
Tablet YBC $7289$ is one of the clay tablets from the Old Babylonian period.
Contents
The sides of the square are marked with the cuneiform numerals for $30$.
Above one of the diagonals is:
- $1; 24, 51, 10$
which is the length of the diagonal of a square of side length $1$.
Below it is:
- $42; 25, 35$
which is its product with $30$.
Thus $42; 25, 35$ is the length of the diagonal of a square of side length $30$.
From Pythagoras's Theorem, the length of the diagonal of a square of side length $1$ is $\sqrt 2$.
The approximation $1; 24, 51, 10$ is correct to $6$ decimal places.
Sources
- 2008: Ian Stewart: Taming the Infinite ... (previous) ... (next): Chapter $2$: The Logic of Shape: The beginnings of geometry