Lesson 1-2Section 1-4

Postulate

Definition

Example 1

Example 2

Definition

Construction

Postulate

Example 3

Example 4

Example 5

What about the distance?

We used the ruler postulate for finding the distance between two points on a line, but how can we find the distance of a line in a coordinate plane?

Let’s see…..

Definition

Example 6

Example 7

Is there another way?

We have now mastered finding the distance between two points in the coordinate plane. However, there is another way of going about it.

We can use a very famous theorem: The Pythagorean Theorem. Let’s see how we do that….

Definition

Example 8

Example 8 cont.

Example 8 cont.

Example 9

Practice

Try the following problems:

Pg. 32 # 5-15 odd , 12