The term "90 degrees" refers to a specific angle in geometry. It represents a quarter of a full rotation, which is 360 degrees. In a right triangle, one of the angles is always 90 degrees, making it a right angle. This angle is crucial in various fields, including architecture and engineering, as it helps create perpendicular lines. In everyday life, "90 degrees" can also describe temperature, particularly in weather reports. For example, a temperature of 90 degrees Fahrenheit indicates a warm day. Understanding this measurement is important for planning outdoor activities and dressing appropriately for the weather.