Question

1. which of the following statements is not a property of parallelograms? opposite sides are parallel. opposite angles are congruent. all sides are parallel.

Explanation:

A parallelogram has opposite sides parallel (by definition), and opposite angles congruent. But not all sides are parallel. Only opposite sides are parallel. For example, in a parallelogram \(ABCD\), \(AB\parallel CD\) and \(AD\parallel BC\), but \(AB\) is not parallel to \(AD\). So the statement “All sides are parallel” is not a property of parallelograms.

Answer:

C. All sides are parallel.