1. Pythagoreans discover irrational numbers. 532 BC 2. Euclid writes Elements. 300 BC 3. Archimedes determines formulas for the area and volume of a sphere. 250 B.C. 4. Eratosthenes determines the circumferences of Earth. 235 B.C. 5. Appollonius studies conic sections. 225 B.C. 6. Al-Khowarizmi uses zero. 830 A.D. 7. Rudolff introduces the radical sign. 1525 A.D. 8. Tartaglia solves cubic equations. 1535 A.D. 9. Recorde introduces the equals sign. 1557 A.D. 10. Stevin introduces decimals. 1585 A.D. 11. Harriot introduces the inequality signs. 1610 A.D. 12. Napier invents …showed first 75 words of 271 total…

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