Prove that the sum of all vectors drawn from the centre of a regular octagon to its vertices is the zero vector.

Prove that the sum of all the vectors drawn from the centre of a regular octagon to its vertices is the null vector.

Prove that the sum of three vectors determined by the medians of a triangle directed from the vertices is zero.

Prove that the sum of three vectors determined by the medians of a triangle directed from the vertices is zero.

Prove that the sum of three vectors determined by the medians of a triangle directed from the vertices is zero.

Prove that the sum of three vectors determined by the medians of a triangle directed from the vertices is zero.

Prove that the sum of three vectors determined by the medians of a triangle directed from the vertices is zero.

Prove that the sum of the vectors represented by the sides of a closed polygon taken in order is a zero vector.

Show that the sum of three vectors determined by the medians of a triangle directed from the vertices is zero.

Show that the sum of three vectors determined by the medians of a triangle directed from the vertices is zero.

Show that the sum of three vectors determined by the medians of a triangle directed from the vertices is zero.