Geometric Interpretation: The Sign of a Product

The product of two positive numbers.

In the following, points

and

start out with

and

. What do you notice about the

coordinate of point

? In other words, is

positive or negative? How do you know?

In the above, move point

so that

and make sure

. Is

positive or negative? How do you know?

Move points

and

so that

and

. Is

positive or negative? How do you know?

Move point

so that

. Move point

so that

. Is

positive or negative? How do you know?

Positive * Positive =

Negative * Positive=

Negative * Negative=

Positive * Negative