Question 569568
I guess you have a rectangular end table, 45 inches  by 48 inches (It’s not a square if the sides’ lengths are different).
You can place books side by side with the 5 inch book side with along the 45 inch rectangle side until you have a row of 9 books
covering (with a row 8 inches high) the 45 inch width:
{{{9*5}}} inches = {{{45}}} inches 
You add rows like that, one after the other and after a total of 6 rows, the whole 48 inch are covered: 6(8”)=48”
{{{6*8}}} inches = {{{48}}} inches
The layer of books covering the 45 inches  by 48 inches space would look like this:
{{{drawing(300,300,-1,54,-4,51,
rectangle(0,0,45,48),
line(5,0,5,48), line(10,0,10,48), line(15,0,15,48), line(20,0,20,48),
line(25,0,25,48), line(30,0,30,48), line(35,0,35,48), line(40,0,40,48),
line(0,8,45,8), line(0,16,45,16), line(0,24,45,24), line(0,32,45,32), line(0,40,45,40), locate(18,0,"45 inches"), locate(45,25,48), locate(45,23,"inches"),arrow(47,25,47,48),arrow(47,20,47,0),
arrow(18,-1.5,0,-1.5),arrow(30,-1.5,45,-1.5))}}}
You placed a total of 9(6)=54 books on the table, 6 rows of 9.