What standard U.S. coin may be used to gauge the space between the line and the brick?

A nickel is commonly used in masonry to assess the space between the mortar joint and the brick. This is primarily because a nickel has a thickness of approximately 1.95 millimeters (or 0.077 inches), which aligns well with the desired joint gap in brickwork. Maintaining consistent joint spacing is crucial for both aesthetic appeal and structural integrity, and the nickel serves as a handy and accessible tool for masonry professionals to measure this spacing accurately.

In masonry practice, using coins to gauge spacing is a practical solution since they are easy to carry, readily available, and offer a uniform measurement. The other options, while also being common coins, do not correspond to the standard joint specifications as effectively as the nickel does. This understanding emphasizes the importance of precision in masonry work for achieving high-quality results.