Problems

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Found: 3

Several points are given and for some pairs (A,B) of these points the vectors AB are taken, and at each point the same number of vectors begin and end. Prove that the sum of all the chosen vectors is 0.

On the sides AB, BC and AC of the triangle ABC points P, M and K are chosen so that the segments AM, BK and CP intersect at one point and AM+BK+CP=0 Prove that P, M and K are the midpoints of the sides of the triangle ABC.