The glass container shown is filled to a height of 2.25 inches. how much sand is currently in the container?

The answer is 50 5/8 in³.

To calculate how much sand is in the container, you need to calculate the volume it takes. The volume (V) of rectangular prism, such as the container is:
V = l * w * h
l - length, l = 5 in
w - width, w = 4 1/2 in = (4 + 1/2) in = (8/2 + 1/2) in = 9/2 in
h - height, h = 2.25 in = (2 + 0.25) in = (2 + 1/4) in = (8/4 + 1/4) in = 9/4 in

The volume of the sand is:
V = 5 * 9/2 * 9/4 = (5 * 9 * 9)/(2 * 4) = 405/8 in³
V = (400 + 5)/8 in³ = (400/8 + 5/8) in³ = 50 + 5/8 in³ = 50 5/8 in³