What size does a #3 rebar represent in inches?

Reinforcement bars, commonly known as rebar, are identified by a numbering system that relates to their size. In this system, the numerical designation correlates directly to the bar's nominal diameter in eighths of an inch. Therefore, a #3 rebar indicates it has a diameter of 3/8 inches. The size designation signifies that the rebar’s diameter is calculated as 3 divided by 8, leading to the measurement of 0.375 inches, which is commonly expressed as 3/8 of an inch. This system helps engineers and construction professionals easily specify the size of rebar required for their projects. In this context, the other answer choices represent incorrect sizes for a #3 rebar.