The glass container is filled to a height of 2.25 inches. what percent of the container is filled with sand?

The complete question in the attached figure

Part A) How much sand is currently in the container?
[sand  currently in the container]=(5)*(4 1/2)*(2.25)-----> (5)*(4.5)*(2.25)
[sand  currently in the container]=50.625 in³

the answer Part a) is 50.625 in³

Part B) How much more sand could the container hold before?
[sand could the container hold before]=[5*4.5*3]-[50.625]
[sand could the container hold before]=[67.5]-[50.625]------> 16.875 in³

the answer Part B) is 16.875 in³

Part C) What percent of the container is filled with sand?
the volume of container is [5*4.5*3]=67.5 in³
the volume filled with sand=50.625 in³
therefore
if 100%----------------> 67.5 in³
 X---------------------> 50.625 in³
X=(50.625*100)/67.5=75 %

the answer Part C) is 75%