An angle greater than 90 degrees is called an obtuse angle. Angles are measured in degrees, and while a right angle is precisely 90 degrees, any angle that exceeds this measurement falls into the obtuse category. Obtuse angles range from just over 90 degrees to less than 180 degrees. They are commonly found in various geometric shapes and can influence the properties of polygons. Understanding obtuse angles is essential in geometry as they help in calculating the interior angles of shapes and contribute to real-world applications, such as architectural design and engineering.