Подошла к концу олимпиада ЮМШ 🥇 Публикуем задачку, которая предлагалась в девятом классе 🔥
Задача. Дан вписанный выпуклый четырёхугольник 𝐴𝐵𝐶𝐷. Точки 𝑃, 𝑄, 𝑅, 𝑆 выбраны на прямых 𝐴𝐷, 𝐴𝐵, 𝐶𝐵, 𝐷𝐶 так, что 𝑃𝑄 ⊥ 𝐴𝐵, 𝑄𝑅 ⊥ 𝐵𝐶, 𝑅𝑆 ⊥ 𝐶𝐷 и 𝑆𝑃 ⊥ 𝐷𝐴. Оказалось, что четырёхугольники 𝑃𝑄𝑅𝑆 и 𝐴𝐵𝐶𝐷 (соответственно) подобны. Докажите, что центр описанной окружности четырёхугольника 𝑃𝑄𝑅𝑆 — это точка пересечения диагоналей 𝐴𝐵𝐶𝐷.
Подошла к концу олимпиада ЮМШ 🥇 Публикуем задачку, которая предлагалась в девятом классе 🔥
Задача. Дан вписанный выпуклый четырёхугольник 𝐴𝐵𝐶𝐷. Точки 𝑃, 𝑄, 𝑅, 𝑆 выбраны на прямых 𝐴𝐷, 𝐴𝐵, 𝐶𝐵, 𝐷𝐶 так, что 𝑃𝑄 ⊥ 𝐴𝐵, 𝑄𝑅 ⊥ 𝐵𝐶, 𝑅𝑆 ⊥ 𝐶𝐷 и 𝑆𝑃 ⊥ 𝐷𝐴. Оказалось, что четырёхугольники 𝑃𝑄𝑅𝑆 и 𝐴𝐵𝐶𝐷 (соответственно) подобны. Докажите, что центр описанной окружности четырёхугольника 𝑃𝑄𝑅𝑆 — это точка пересечения диагоналей 𝐴𝐵𝐶𝐷.
This ability to mix the public and the private, as well as the ability to use bots to engage with users has proved to be problematic. In early 2021, a database selling phone numbers pulled from Facebook was selling numbers for $20 per lookup. Similarly, security researchers found a network of deepfake bots on the platform that were generating images of people submitted by users to create non-consensual imagery, some of which involved children. Markets continued to grapple with the economic and corporate earnings implications relating to the Russia-Ukraine conflict. “We have a ton of uncertainty right now,” said Stephanie Link, chief investment strategist and portfolio manager at Hightower Advisors. “We’re dealing with a war, we’re dealing with inflation. We don’t know what it means to earnings.” It is unclear who runs the account, although Russia's official Ministry of Foreign Affairs Twitter account promoted the Telegram channel on Saturday and claimed it was operated by "a group of experts & journalists." Additionally, investors are often instructed to deposit monies into personal bank accounts of individuals who claim to represent a legitimate entity, and/or into an unrelated corporate account. To lend credence and to lure unsuspecting victims, perpetrators usually claim that their entity and/or the investment schemes are approved by financial authorities. Emerson Brooking, a disinformation expert at the Atlantic Council's Digital Forensic Research Lab, said: "Back in the Wild West period of content moderation, like 2014 or 2015, maybe they could have gotten away with it, but it stands in marked contrast with how other companies run themselves today."
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