Definition of the word right angle

The term "right angle" stems from the Latin word "rectus," which means "straight" or "upright." In geometry, a right angle refers to an angle between two lines that measures exactly 90 degrees or a quarter turn. The ancient Greek mathematicians Pythagoras and Euclid recognized and named the concept of a right angle over 2,000 years ago. The Greeks measured angles using taking the intersection of two lines, known as a vertex, and then measuring the angles formed by the vertex and the lines extending from it. The concept of right angles has important applications in various fields, including architecture, engineering, carpentry, and science. Carpenters and architects use right angles when constructing buildings and furniture, while engineers use it in designing and constructing machines and structural components. In mathematics, the notion of right angles is crucial to understanding and mastering geometry. It allows for defining perpendicular lines, constructing and measuring right triangles, and computing the sine, cosine, and tangent functions, which are essential in solving trigonometric problems. In summary, the term "right angle" originates from the Latin word "rectus," and its significance has transcended through various fields, highlighting its practical and theoretical importance in mathematics, science, and engineering.