Stamps
Scott: 245 A57
Scott:
Scott:
Zhang Heng was a Chinese astronomer, mathematician, and expert in many other areas. While the previous Chinese estimate of pi was 3, Heng initially computed an estimate by dividing 736 by 232 to obtain 3.1724. Heng later improved the estimate to the square root of 10 or 3.162 and then to 730 divided by 232 to obtain 3.1466.
| Stamp | Description |
|---|---|
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China, 8f, 1955 Scott: 245 A57 |
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Malawi, k200, 2008 Scott: |
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Mali, 1400f, 2011 Scott: |