be midpoints of an equilateral triangle . be point lie on incircle of .

Prove that

Author: Van Khea, Cambodia

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Line tangent to incircle of an equilateral triangle at .

Prove that

Author: Van Khea, Cambodia

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is an equilateral triangle. Prove that:

Author: Van Khea, Cambodia

Filed under: Uncategorized ]]>

Let .

Prove that

Author: Van Khea, Cambodia

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Let be circumcenter of triangle .

Prove that:

Author: Van Khea, Cambodia

Filed under: Uncategorized ]]>

Let be midpoints of an equilateral triangle . Let be midpoint of . Prove that:

Author: Van Khea, Cambodia

Filed under: Uncategorized ]]>

is an equilateral triangle.

is midpoints of and

Prove that

Proposed by Van Khea, Cambodia

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Let be circumcenter of an equilateral triangle and let be point lie on incircle. Prove that:

Author: Van Khea, Cambodia

Filed under: Uncategorized ]]>

Let be point lie on circumcircle of an equilateral triangle . Let

Prove that

Author: Van Khea, Cambodia

Filed under: Uncategorized ]]>

Let be point lie on circumcircle of an equilateral triangle .

Let be projection points from to .

Prove that

Prove that

Author: Van Khea, Cambodia

Filed under: Uncategorized ]]>