Here's how to calculate the volume of a standard-size brick:

1. Convert mixed numbers to fractions:

* 2 1/4 inches = (2 * 4 + 1) / 4 = 9/4 inches

* 3 3/4 inches = (3 * 4 + 3) / 4 = 15/4 inches

2. Calculate the volume:

* Volume = Length x Width x Depth

* Volume = 8 inches * 9/4 inches * 15/4 inches

* Volume = 270 cubic inches

Therefore, the volume of the standard-size brick is 270 cubic inches.