What is the correct angle of inclination for single and extension ladders?

The correct angle of inclination for single and extension ladders is approximately 75 degrees. This angle is optimal because it provides a stable setup that maximizes the ladder's safety and usability. When the ladder is positioned at this angle, it ensures that the base is far enough from the wall to allow for effective weight distribution and to prevent tipping. A 75-degree angle strikes a balance between being too steep, which could increase the risk of slipping, and too shallow, which may compromise stability. Using this angle helps users to maintain a secure grip and center their weight properly while working at height, reducing the likelihood of accidents.