Current location - Training Enrollment Network - Mathematics courses - The mathematical proof proposition of the second day of junior high school is that "two groups of quadrangles with equal opposite sides are parallelograms"
The mathematical proof proposition of the second day of junior high school is that "two groups of quadrangles with equal opposite sides are parallelograms"
Question: In quadrilateral ABCD, AB=CD, BC=DA. Verify that quadrilateral ABCD is a parallelogram.

It is proved that in quadrilateral ABCD, connecting AC, triangle ABC and triangle CDA, using AB = CD, BC = DA, AC * * * so triangle ABC and triangle CDA are congruent, so angle BAC= angle DCA, angle DAC= angle BCA, so AB//DC and AD//BC, so quadrilateral ABCD is a parallelogram.

Is another "true proposition"? Questions like this are generally false, right? " Not necessarily.