# badboyhalofanart skeppyfanart mtbos iteachmath math maths geometry hsmath collegemath proof figurethat triangle incenter angle teachers highschool quadrilateral euclid collinearity concurrency

Any 1 Quadrilateral + Bisectors of its 4 Exterior Angles = 😮? How can we formally prove what is dynamically illustrated here? 🤔 (Source: ). https://t.co/27521S487E.

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2019-02-25