What is the sum of two supplementary angles?

Two angles are considered supplementary if the sum of their measures equals 180 degrees. This definition is fundamental in geometry and is commonly used in various applications within mathematics.

For example, when two angles are placed adjacent to each other and form a straight line, the measures of these angles will add up to 180 degrees. This relationship is crucial in solving problems involving angle measures, especially in triangles and various geometric shapes.

Therefore, the sum of two supplementary angles will always result in 180 degrees, making this choice the correct answer.