A straight angle is an angle that measures exactly 180 degrees. It is formed when two rays point in exactly opposite directions, creating a straight line. This type of angle is often represented visually as a straight line, making it easy to identify in various geometric shapes. In geometry, straight angles are important because they help define the relationships between different angles. For example, when two angles add up to a straight angle, they are called supplementary angles. Understanding straight angles is essential for studying more complex geometric concepts and shapes, such as triangles and polygons.