The grid used on the sides of the slab's main field uses which dimensions?

• A. 10 by 12
• B. 12 by 14
• C. 15 by 18
• D. 8 by 16

Answer: (C)

Understand that a standard grid is used to subdivide the sides of the slab’s main field so measurements and layout can be counted consistently. The grid size of 15 by 18 inches is chosen because it strikes a practical balance: the squares are large enough to count quickly and estimate areas or volumes, yet small enough to keep calculations precise. This standard also aligns with common field practices and forms, making layout and verification straightforward. Other grid sizes would create too many tiny squares or too few large ones, reducing ease of use and accuracy.