If a portable ladder has a working length of 16 feet, how far should the base be from the wall for proper angle?

• A. 2 feet
• B. 4 feet
• C. 6 feet
• D. 8 feet

Answer: (B)

Safe ladder setup hinges on getting the right angle. A reliable guideline is the 4:1 rule: for every 4 feet of ladder height, place the base about 1 foot away from the wall. With a 16-foot ladder, that means the base should be about 4 feet out. This puts you in a angle around 75 degrees, which helps maintain stability. You can check this with a quick geometry check: the ladder length is the hypotenuse (16 ft), the base is 4 ft, so the vertical height is sqrt(16^2 - 4^2) ≈ 15.5 ft. The bottom angle satisfies tan(theta) = vertical/base ≈ 15.5/4 ≈ 3.87, giving theta ≈ 75 degrees. At this angle the ladder is less likely to slip or tip. If the base were closer, the angle would be steeper and less stable; if farther, the angle would be too shallow and also risky.