Question

Each book is the same size. Isolde knows the area of the base of one book is 22 1/2 square inches and each book is 3/4 inch thick.

The volume of a stack of 9 books is ? cubic inches.

Answer 1

Volume = Area of base * height

You are given area of base = 22 1/2 or 22.5
and height = 3/4 or 0.75

To find the volume of one book, just multiply the two numbers.

To find the volume of 9 books, you then multiply by 9.
The volume of 9 books is going to be 9 times the volume of 1 book.

Does that make sense to you?