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 ]]>

Let be point lie on of . Let and be incenters of and . Let be circumcenters of .

Prove that are collinear.

Author: Van Khea, Cambodia

Filed under: Uncategorized ]]>

Given an equilateral triangle . Let be point on . Let and be incenter of and . Let be circumcenter of .

Prove that is an equilateral triangle.

Author: Van Khea, Cambodia

Filed under: Uncategorized ]]>

Prove that .

Author: Van Khea, Cambodia

Filed under: Uncategorized ]]>

Let be square and let be midpoints. For any point inside of square , Prove that:

. ( )

Author: Van Khea, Cambodia

Filed under: Uncategorized ]]>

Let circle inscribe in square . Let be point lie on circle .

Prove that

Author: VanKhea, Cambodia

Filed under: Uncategorized ]]>

Let be incenter of an equilateral triangle . Let be any point and let be projection points from to the sides .

Prove that

Author: Van Khea, Cambodia

Filed under: Uncategorized ]]>

Let be circumcenter of an equilateral triangle and let be any point in the plan.

Prove that

Author: Van Khea, Cambodia

Filed under: Uncategorized ]]>