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  1. The special case of Miquel's theorem when points are collinear | plane geometry | intermediate level

    The special case of Miquel's theorem when points are collinear | plane geometry | intermediate level

    20
  2. Korean Practice; fifth vocab sheet, "intermediate", Part 2

    Korean Practice; fifth vocab sheet, "intermediate", Part 2

    2
  3. The altitudes of a triangle are bisectors in the orthic triangle | plane geometry | intermediate

    The altitudes of a triangle are bisectors in the orthic triangle | plane geometry | intermediate

    14
  4. Segments connecting midpoints of opposite arcs of circumcircle of quadril. | geometry | intermediate

    Segments connecting midpoints of opposite arcs of circumcircle of quadril. | geometry | intermediate

    23
  5. Segments at equal angles from the opposite sides of a cyclic quadrilateral | geometry | intermediate

    Segments at equal angles from the opposite sides of a cyclic quadrilateral | geometry | intermediate

    24
  6. De Longchamps theorem about perpendicular bisectors of angle bisectors | geometry | intermediate

    De Longchamps theorem about perpendicular bisectors of angle bisectors | geometry | intermediate

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  7. Bisectors of angles between opposite sides of a cyclic quadrilateral | plane geometry | intermediate

    Bisectors of angles between opposite sides of a cyclic quadrilateral | plane geometry | intermediate

    23
  8. Parallelogram formed by midpoints of sides of a quadrilateral | plane geometry | intermediate level

    Parallelogram formed by midpoints of sides of a quadrilateral | plane geometry | intermediate level

    29
  10. The tangential quadrilateral formed by centers of 4 tangent circles | plane geometry | intermediate

    The tangential quadrilateral formed by centers of 4 tangent circles | plane geometry | intermediate

    9
  11. Segments between tangency points on opposite sides of a quadrilateral | geometry | intermediate

    Segments between tangency points on opposite sides of a quadrilateral | geometry | intermediate

    23
    1
  12. Segments connecting midpoints of opposite sides of a quadrilateral | plane geometry | intermediate

    Segments connecting midpoints of opposite sides of a quadrilateral | plane geometry | intermediate

    16
  13. A theorem about two circles intersecting on the sides of a triangle | plane geometry | intermediate

    A theorem about two circles intersecting on the sides of a triangle | plane geometry | intermediate

    2
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    1
  14. Reflections of orthocenter with respect to sides of triangle | plane geometry | intermediate level

    Reflections of orthocenter with respect to sides of triangle | plane geometry | intermediate level

    19
  15. Reflections of line passing through orthocenter of triangle | plane geometry | intermediate level

    Reflections of line passing through orthocenter of triangle | plane geometry | intermediate level

    38
    1
  17. Cyclic quadrilateral formed by inscribed angle from the midpoint of an arc | geometry | intermediate

    Cyclic quadrilateral formed by inscribed angle from the midpoint of an arc | geometry | intermediate

    34
  18. The cyclic quadrilateral formed by the external bisectors of a quadr. | geometry | intermediate

    The cyclic quadrilateral formed by the external bisectors of a quadr. | geometry | intermediate

    33
  19. Deriving Ceva's theorem from Menelaus's theorem | plane geometry | intermediate level

    Deriving Ceva's theorem from Menelaus's theorem | plane geometry | intermediate level

    15
  20. The cyclic quadrilateral formed by the bisectors of a quadrilateral | plane geometry | intermediate

    The cyclic quadrilateral formed by the bisectors of a quadrilateral | plane geometry | intermediate

    15
  22. The Bevan point of a triangle | plane geometry | intermediate level

    The Bevan point of a triangle | plane geometry | intermediate level

    31
  23. The angles between sides of triangle and altitude and circumcenter | plane geometry | intermediate

    The angles between sides of triangle and altitude and circumcenter | plane geometry | intermediate

    34
  24. Reflections of foot of altitude of triangle with respect to sides | plane geometry | intermediate

    Reflections of foot of altitude of triangle with respect to sides | plane geometry | intermediate

    18