3
No, a quadrilateral with congruent diagonals but no right angles is not necessarily a parallelogram. In order for a quadrilateral to be classified as a parallelogram, it must have both pairs of opposite sides parallel. The property of having congruent diagonals does not guarantee that the sides are parallel, so the quadrilateral may not be a parallelogram.
There are no right angles in a parallelogram. A parallelogram only has right angles if it is a rectangle, in which case it has exactly four.
2 pairs
Parallelogram have 4 right angles. (because, square and rectangle is also parallelogram)
There are 4 right angles in a parallelogram.
A parallelogram, in general, has no right angles.
none
4
It is not a requirement that any of the angles are right angles (90 degrees), to qualify as a parallelogram.
A parallelogram has 0 or 2 acute angles. If the parallelogram happens to have four right-angled corners, it is still a parallelogram (and a rectangle), but no acute angles.
Usually zero. If your parallelogram happens to be a rectangle, 4.
it has 0