Answer:
<h2>V = 605 in³</h2>
Step-by-step explanation:
The formula of a volume of a pyramid:

B - area of a base
H - height
We have the square in the base with side length a = 11 in.
Area of a base:

Calculate the volume:

You can tell that a line is parallel if the lines can go on forever without crossing or intersecting. A line is perpendicular when the lines intersect at a right angle. If the slopes are either equal or negative reciprocals, they cannot be parallel or perpendicular.
Hope this helps you!
I'd do 9x4=36 because the 9 is from your money and the 4 is from your books. Now since you want to find out how much 4 books cost you just multiply that by 9