First point to be noted here is, the shelf and the book are 5 inches wide. So it is perfect to hold the book.
The shelf is 56 inches tall and the book is 4 inches thick. To find the number of books Linda can arrange on the shelf, just divide 56 by 4
Number of books Linda can arrange on the shelf = 56 ÷ 4 = 14 books
A right angle= 90
90 x 5/3 = 150
Has a height of 12, because 12*9*5=180
