By using vectors prove that a quadrilateral is a parallelogram if and only if the diagonals bisect each other.

Write each of the following statements in the form "if-then" i. You get a job implies that your credentials are good. ii. The bannana trees will bloom if it stays warm for a month. iii. A quadrilateral is a parallelogram if its diagonals bisect each other. iv. to get an A^(+) in the class, it is necessary that you do all the exercises of the book.

Using vectors prove that the diagonals of a parallelogram bisect each other.

When proving that a quadrilateral is a parallelogram by using slopes you must find

Using vector method, prove that if the diagonals of a parallelogram are equal, then it is a rectangle.

Using dot product of vectors, prove that a parallelogram, whose diagonals are equal, is a rectangle

Prove using vectors the mid-points of two opposite sides of a quadrilateral and the mid-points of the diagonals are the vertices of a parallelogram.

The vector vec(AB)=3hati+2hatj+2hatk and vec(BC)= - hati-2hatk are adjacent sides of a parallelogram ABCD the angle between the diagonals is :