What is the recommended angle between the ladder and the floor?

What is the recommended angle between the ladder and the floor?

• A. 75.5 degrees
• B. 60 degrees
• C. 45 degrees
• D. 90 degrees

Answer: (A)

The safe, recommended angle for a leaning ladder is about 75 degrees from the floor. This comes from the common 4:1 rule: for every 4 feet of ladder height up the wall, place the base about 1 foot out from the wall. In a right triangle, tan θ = height/base, and with base = height/4, tan θ = 4, so θ = arctan(4) ≈ 75.96 degrees. That places the ladder in a stable position where it’s not too steep to slip at the base or too shallow to tip backward. So about 75.5 degrees is a close, practical value. The other angles are either too shallow or too vertical for safe use.

The safe, recommended angle for a leaning ladder is about 75 degrees from the floor. This comes from the common 4:1 rule: for every 4 feet of ladder height up the wall, place the base about 1 foot out from the wall. In a right triangle, tan θ = height/base, and with base = height/4, tan θ = 4, so θ = arctan(4) ≈ 75.96 degrees. That places the ladder in a stable position where it’s not too steep to slip at the base or too shallow to tip backward. So about 75.5 degrees is a close, practical value. The other angles are either too shallow or too vertical for safe use.