Find the length of red arc AB
Find the length of red arc AB (r1=1, r2=2). Express result to the accuracy of 3 decimal.Correct answers: 43
The first user who solved this task is Roxana zavari.
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Cotton ginIn 1794, Eli Whitney was issued a U.S. patent for his cotton gin. His invention replaced much processing by hand labour, and revolutionized the textile industry. Cotton became commercially important in the southern US, with a resulting demand for slaves to tend the fields and harvest the cotton crops.[Image: detail from copy of Whitney's patent made by the Patent Office in 1845.] |