Question

Prove that the diagonals of a rectangle bisect each other.

The midpoints are the same point, so the diagonals _____



are parallel to each other.


bisect each other.


have the same slope.


are perpendicular to each other.

Answer 1

bisect each other.

Explanation:

The midpoints are the same point, so the diagonals bisect each other.

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More elaboration on a proof

The alternate interior angles formed by diagonals and the sides of the triangle are congruent, so the (point-to-point) triangles formed by the crossing diagonals are congruent ASA. Since the sides of those triangles are congruent, the diagonals meet at their midpoints. That is, the diagonals bisect each other.