Answer: The angle that measures 90 degrees is called the right angle.
In detail, an angle that measures 90 degrees is known as a right angle. It is a fundamental concept in geometry and is characterized by the perfect quarter-turn formed when two lines or line segments intersect each other perpendicular to each other. This intersection creates four angles, each measuring 90 degrees.
A right angle is denoted by the symbol “∟” or by a small square at the vertex of the angle. In diagrams and geometric figures, it is often represented as a small square or a square corner.
The significance of a right angle lies in its role in defining various geometric shapes and concepts. For example:
- Right triangles: A right triangle is a triangle that contains one right angle.
- Rectangles and squares: In rectangles and squares, all four interior angles are right angles.
- Perpendicular lines: Two lines are perpendicular if they intersect at a right angle.
- Coordinate geometry: In the Cartesian coordinate system, the x-axis and y-axis are perpendicular to each other, forming right angles at their intersection, called the origin.
Right angles play a crucial role in many practical applications, including architecture, engineering, construction, and navigation. They provide a precise and standardized way to measure and describe angles and geometric shapes, making them essential in various fields of mathematics and science.