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Parallelogram Diagonals Theorem
See It in Action
Two examples of the idea done right—and one common look-alike that is not right.
EXAMPLE
EXAMPLE
NON-EXAMPLE
Statement
If a quadrilateral is a parallelogram, then the diagonals of the quadrilateral bisect each other.
In simple terms:
In a shape is a parallelogram, then each diagonal must cut the other exactly in half.
Example:
Since ABCD is a parallelogram, and diagonals AC and BD intersect at point E, then AE=CE and BE=DE.
Why It Matters:
This property is often used to prove a quadrilateral is a parallelogram or to solve for unknown segment lengths.
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