Which statement is always true? a. linear pairs of angles are congruent b. vertical angles are supplementary c. adjacent angles are complementary d. adjacent linear pairs of angles are supplementary?

Two angles are said to be linear if they are adjacent angles formed by two intersecting lines. The sum of a linear pair of angles is 180 degrees, hence are supplementary.
Linear pairs of angles can only be congruent when the measure of each of the angles is 90 degrees.
Linear pairs of angles are not always congruent.

Vertical angles are each of the pairs of opposite angles made by two intersecting lines.
Vertical angles are always equal.
Vertical angles can only be supplementary, when the measure of each of the angles is 90 degrees.
Vertical angles are not always supplementary.

Adjacent angles are two angles that have a common vertex and a common side.
Each of the two angles can assume any value and hence adjacent angles are not always complementary.

Therefore, the only statement that is always true is that "adjacent linear pairs of angles are supplementary"

The statement that is always true is: D. adjacent linear pairs of angles are supplementary.

What are Linear Pairs of Angles?

Linear pairs of angles are angles that lie on the straight line. The sum of a linear pair is always 180 degrees, thus, they are regarded as supplementary angles.

Therefore, the statement that is always true is: D. adjacent linear pairs of angles are supplementary.

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