Sphaerica

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Queen Elizabeth II addresses at opening of Parliament. (Date unknown on photo, but may be 1958, the first time the opening of Parliament was filmed.)

All 119 References in “We Didn’t Start the Fire,” Explained

Korean War - U.S. Marines watch explosions of bombs dropped by Marine Vought F4U Corsair fighter bomber planes during the Battle of Chosin Reservoir, Korea, in December 1950. soldiers

Korean War Timeline

The Castillo, a Toltec-style pyramid, rises 79 feet (24 meters) above the plaza at Chichen Itza in Yucatan state, Mexico. The pyramid was built after invaders conquered the ancient Maya city in the tenth century.

What’s Inside the Pyramid at Chichén Itzá?

Sydney New Years Eve Fireworks

Why Does the New Year Start on January 1?

Ahura Mazda - relief of the Zoroastrian god Ahura Mazda at the ancient ruins of Persepolis in Iran. Also known as Ormazd Zoroastrianism,

Which Religion Is the Oldest?

Shadow of a man holding large knife in his hand inside of some dark, spooky buiding

7 of History's Most Notorious Serial Killers

Mayer Amschel Rothschild (1744-1855), founder of the house of Rothschild; lithograph by Friedrich Lieder, c. 1830.

Where Do Antisemitic Conspiracy Theories About the Rothschild Family Come From?

Sphaerica

work by Menelaus of Alexandria

Learn about this topic in these articles:

contribution to trigonometry

In trigonometry: Passage to Europe
…in Book 1 of the Sphaerica, a three-book treatise by Menelaus of Alexandria (c. 100 ce) in which Menelaus developed the spherical equivalents of Euclid’s propositions for planar triangles. A spherical triangle was understood to mean a figure formed on the surface of a sphere by three arcs of great…
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discussed in biography

In Menelaus of Alexandria
Menelaus’s most important work is Sphaerica, on the geometry of the sphere, extant only in an Arabic translation. In Book I he established the basis for a mathematical treatment of spherical triangles analogous to Euclid’s treatment of plane triangles. Furthermore, he originated the use of arcs of great circles instead…
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