# CHAPTER 15 — Product of Rectangular Matrices

This chapter discusses the product of
two rectangular matrices.
This product is an extension of the
ideas of the previous chapter.
Each element of the product is formed by
a dot product.

#### Chapter Topics:

- Dimensions of matrices that can be multiplied.
- Element of result formed by dot product.
- Associative property.
- Not commutative.
- Distributive over addition.
- Product of zero matrix.

Matrix-matrix products are used in computer
graphics to create the transformation matrices
that operate on points and vectors.
In a "first person game" such as DOOM the
landscape is modeled with points and vectors.
The constantly changing view you see
as the hero moves
through the landscape is created by transforming
those points and vectors.