At what angle should an extension ladder be placed?

The recommended angle for placing an extension ladder to ensure stability and safety is commonly expressed using the rule of a quarter of its height as the distance from the wall. This means that for every four feet of ladder height, the base should be positioned one foot away from the structure it is leaning against. This creates an approximate angle of 75 degrees from the ground, which is within optimal limits for maintaining balance and preventing slipping.

The other options do not adhere to this standard practice as precisely. While some may suggest angles that fall within the general range of safe placement, they might not provide the exact guidelines necessary for maximizing safety while using ladders. Most importantly, ensuring that a ladder is set at the correct angle mitigates the risk of accidents that can occur due to improper use.