97 is the answer to your question
One irrational number between 5 and 7 is

.
Prism volume = width*length*height
56 1/4 = 3 3/4 * 7 1/2 * h
56.25=3.75*7.5*h
h=(56.25)/(3.75*7.5)=2
So that the missing dimension (height) is 2 ft
Rahul use addition property of equality in step 2.
Solution:
The image of the question is attached below.
Step 1:

combine like terms together.

To make the denominator same multiply and divide 2x by 5.
Step 2:

By addition property of equality, add
on both side of the equation.

Step 3:

Step 4:
Multiply by
on both side of the equation.

Hence Rahul use addition property of equality in step 2.
60% is the answer you are seeking.