What is the minimum base distance for a straight ladder according to the 4:1 rule?

What is the minimum base distance for a straight ladder according to the 4:1 rule?

• A. One-half of the working height.
• B. One-third of the working height.
• C. One-quarter of the working height.
• D. The full working height from the wall.

Answer: (C)

The 4:1 rule says the base distance from the wall should be one-quarter of the working height to keep the ladder at a safe angle. This yields about a 75-degree lean, which balances stability and reach. For example, if you can reach 12 feet, the base should be about 3 feet from the wall. Distances like half or one-third of the working height give a much shallower angle and reduce stability, while placing the base at the full working height would be nearly vertical and unsafe. The minimum base distance, therefore, is one-quarter of the working height.

The 4:1 rule says the base distance from the wall should be one-quarter of the working height to keep the ladder at a safe angle. This yields about a 75-degree lean, which balances stability and reach. For example, if you can reach 12 feet, the base should be about 3 feet from the wall. Distances like half or one-third of the working height give a much shallower angle and reduce stability, while placing the base at the full working height would be nearly vertical and unsafe. The minimum base distance, therefore, is one-quarter of the working height.