There are three types of mounting angles to consider: ______, _______ , and _________.

• A. radial / leading / trailing
• B. radial / axial / tangential
• C. vertical / horizontal / diagonal
• D. circumferential, radial, and axial

Answer: (A)

The key idea is how a mounting surface can tilt in three distinct directions relative to the shaft and its rotation. The three directions to check are radial, leading, and trailing. The radial angle measures tilt away from the shaft’s centerline in the plane that contains the shaft, directly affecting how true the component sits perpendicular to the shaft. The leading and trailing angles describe tilt around the circumference as you look along the shaft—one toward the direction of rotation (leading) and the other opposite that direction (trailing). Together, these capture how the mounting face can tilt around the shaft in the most relevant ways for alignment and clearance during operation. Other option sets use terms like axial, tangential, vertical/horizontal, or circumferential, which don’t match the conventional way these mounting directions are described in this context, so radial/leading/trailing is the best fit.