Обобщение одного известного факта про точку Болтая...
Четырёхугольник ABCD вписан в окружность с центром O. E - точка пересечения его диагоналей, F - точка пересечения продолжений сторон AB и CD, Б - проекция Ο на EF. На сторонах AB и CD, как на основаниях, во внешнюю сторону построены подобные равнобедренные треугольники ABX и CDY. Докажите, что точки O, Б, X, Y лежат на одной окружности.
Обобщение одного известного факта про точку Болтая...
Четырёхугольник ABCD вписан в окружность с центром O. E - точка пересечения его диагоналей, F - точка пересечения продолжений сторон AB и CD, Б - проекция Ο на EF. На сторонах AB и CD, как на основаниях, во внешнюю сторону построены подобные равнобедренные треугольники ABX и CDY. Докажите, что точки O, Б, X, Y лежат на одной окружности.
Update March 8, 2022: EFF has clarified that Channels and Groups are not fully encrypted, end-to-end, updated our post to link to Telegram’s FAQ for Cloud and Secret chats, updated to clarify that auto-delete is available for group and channel admins, and added some additional links. Perpetrators of these scams will create a public group on Telegram to promote these investment packages that are usually accompanied by fake testimonies and sometimes advertised as being Shariah-compliant. Interested investors will be asked to directly message the representatives to begin investing in the various investment packages offered. But Kliuchnikov, the Ukranian now in France, said he will use Signal or WhatsApp for sensitive conversations, but questions around privacy on Telegram do not give him pause when it comes to sharing information about the war. "The argument from Telegram is, 'You should trust us because we tell you that we're trustworthy,'" Maréchal said. "It's really in the eye of the beholder whether that's something you want to buy into." On Telegram’s website, it says that Pavel Durov “supports Telegram financially and ideologically while Nikolai (Duvov)’s input is technological.” Currently, the Telegram team is based in Dubai, having moved around from Berlin, London and Singapore after departing Russia. Meanwhile, the company which owns Telegram is registered in the British Virgin Islands.
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