Definition Picture

Collinear

Noncollinear

You can assume . . . You should NEVER assume . . .

Name _________________________

Date _______________ Period ____ Geo

Notes

1.3

1.3 The ABC’s Assumptions, Betweenness, Collinearity

: Recognize collinear and non collinear points, when a point is between two

others, and apply the triangle inequality.

Collinear vs. Noncollinear

C

B Betweenness & The Triangle Inequality

In order to say a point is BETWEEN two other

points:

__________________________________________

__________________________________________

A T R

X

O

Y

The Triangle Inequality:

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_________________________________________

_________________________________________

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X

20

13

What range of values can x be in?

Note:

11

14

24

Let’s add some algebra . . .

1. Determine the value of x in the diagram shown. 2. What range of values could x be in?

3. What is the measure of ABC?

X

20

13

2512'40''

A

B D

C

(6x - 32) (4x - 8)8

10 4x + 2

2512'40''

A

B D

C

A

I can

assume .

. .

I cannot

assume . .

.

A

B

C

D

E