Question

A triangle is shown with a line extending from the bottom left point
Which statement regarding the interior and exterior angles of a triangle is always true?

An exterior angle is supplementary to the adjacent interior angle.
An adjacent interior angle is supplementary to a remote interior angle.
A remote interior angle is congruent to the exterior angle.
An exterior angle is supplementary to a remote interior angle.

Answer 1

Correct answer: An exterior angle is supplementary to the adjacent interior angle.

Reason: An exterior angle and the interior angle next to it form a linear pair, so they sum to 180°. (In contrast, an exterior angle equals the sum of the two remote interior angles, not congruent or necessarily supplementary to either one individually.)