Which term denotes the vertical surface between steps?

Which term denotes the vertical surface between steps?

• A. Tread
• B. Riser
• C. Protractor
• D. Track

Answer: (B)

The vertical surface between steps is called the riser. In stairs, each step has a horizontal surface you stand on—the tread—and the vertical face just above it is the riser, which defines the height difference to the next step. Escalator and moving-walk steps follow the same idea: a tread for footing and a riser forming the vertical face between steps. The other terms don’t fit: a protractor is a measuring tool for angles, not part of the step anatomy; a track refers to the guiding path or rail, not the vertical face.

The vertical surface between steps is called the riser. In stairs, each step has a horizontal surface you stand on—the tread—and the vertical face just above it is the riser, which defines the height difference to the next step. Escalator and moving-walk steps follow the same idea: a tread for footing and a riser forming the vertical face between steps. The other terms don’t fit: a protractor is a measuring tool for angles, not part of the step anatomy; a track refers to the guiding path or rail, not the vertical face.