Answer:
right
Step-by-step explanation:
Vertical angles are congruent.
A pair of <em>right angles</em> is the only kind of pair of congruent angles that is supplementary.
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An acute angle will be supplementary to an obtuse angle, and vice versa.
A straight angle measures 180°, so is only supplementary to one that measures 0°.
The coordinate would be (-1, -1)