Задача. На сторонах 𝐴𝐵 и 𝐴𝐶 треугольника 𝐴𝐵𝐶 выбраны точки 𝑃 и 𝑄 соответственно такие, что 𝐴𝑃 = 𝐴𝑄. На стороне 𝐵𝐶 выбраны точки 𝑅 и 𝑆 (𝐵𝑅 > 𝐵𝑆) таким образом, что ∠𝐵𝑅𝑃 = ∠𝐵𝑃𝑆 и ∠𝐶𝑆𝑄 = ∠𝐶𝑄𝑅. Докажите, что точки 𝑃, 𝑄, 𝑅, 𝑆 лежат на одной окружности.
Задача. На сторонах 𝐴𝐵 и 𝐴𝐶 треугольника 𝐴𝐵𝐶 выбраны точки 𝑃 и 𝑄 соответственно такие, что 𝐴𝑃 = 𝐴𝑄. На стороне 𝐵𝐶 выбраны точки 𝑅 и 𝑆 (𝐵𝑅 > 𝐵𝑆) таким образом, что ∠𝐵𝑅𝑃 = ∠𝐵𝑃𝑆 и ∠𝐶𝑆𝑄 = ∠𝐶𝑄𝑅. Докажите, что точки 𝑃, 𝑄, 𝑅, 𝑆 лежат на одной окружности.
Unlike Silicon Valley giants such as Facebook and Twitter, which run very public anti-disinformation programs, Brooking said: "Telegram is famously lax or absent in its content moderation policy." But because group chats and the channel features are not end-to-end encrypted, Galperin said user privacy is potentially under threat. "There is a significant risk of insider threat or hacking of Telegram systems that could expose all of these chats to the Russian government," said Eva Galperin with the Electronic Frontier Foundation, which has called for Telegram to improve its privacy practices. "There are several million Russians who can lift their head up from propaganda and try to look for other sources, and I'd say that most look for it on Telegram," he said. 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."
from us
