In what plane is the ladder height measured?

• A. In a vertical plane with the ladder at maximum elevation and extension.
• B. In a horizontal plane at floor level.
• C. In a diagonal plane from ground to top.
• D. In a curved plane around the truck.

Answer: (A)

Ladder height is the vertical distance the top reaches above the ground, so it’s measured in a vertical plane. This side-on plane reflects the true vertical reach you’ll be working with when you climb, regardless of how far the base is placed from the wall or truck. Measuring in a vertical plane keeps the height an accurate representation of how high you can safely access.

A horizontal plane would only tell you how far the base or top sits along the floor, not how high you reach. A diagonal plane from ground to top would mix vertical and horizontal components, which doesn’t give a true vertical height. A curved plane around the truck isn’t a meaningful way to define the ladder’s vertical reach either.