Question

If two angles are supplementary, then they are a linear pair of angles. Is this true or false?

Answer 1

Not necessarily true.
True, if they are adjacent and share a vertex and one side. See the first picture below.
They might not form a linear pair, like in a parallelogram.
See the second picture.

Explanation:

Linear pair forms two supplementary angles.

Supplementary angles `a` and `b` do not form linear pair.