Question

Does every parallelogram have at least one right angle?

Answer 1

No, parallelogram can have any pair of supplementary angles as its adjacent interior angles.
For instance, four angles might be `80^o`, `100^o`, `80^o` and `100^o`.

Explanation:

An example of a parallelogram with no right angles.

By the way, if one angle of a parallelogram is the right angle, all its interior angles are right and it's a rectangle.