Which of the following colors is considered secondary?

The concept of primary and secondary colors is fundamental in color theory, particularly in contexts such as art, design, and hair coloring. Primary colors are those that cannot be created by mixing other colors; these include blue, yellow, and red. Secondary colors, on the other hand, are created by mixing two primary colors in equal measure.

Orange, which is the correct answer, is classified as a secondary color because it is formed by mixing red and yellow. This relationship is not just theoretical; it has practical implications in hair coloring, where understanding color mixing helps colorists achieve the desired shades and tones.

In contrast, blue, yellow, and red are all primary colors, as they serve as the building blocks for creating other colors. Thus, recognizing orange as a secondary color demonstrates an understanding of the foundational principles of color theory.