CK12 - Geometry

8.

9..

10. False.For a counterexample,supposetwo acuteanglesmeasure and , then the sum of those

anglesis , but is still acute.See the diagramfor a counterexample:

Segmentsand Angles

LearningObjectives

• Understandand identifycongruentline segments.


• Identifythe midpointof line segments.


• Identifythe bisectorof a line segment.


• Understandand identifycongruentangles.


• Understandand applythe AngleBisectorPostulate.

Introduction

Now that you havea betterunderstandingof segments,angles,rays,and otherbasicgeometricshapes,
we can studythe waysin whichthey can be divided.Any time you comeacrossa segmentor an angle,
thereare differentwaysto separateit into parts.

CongruentLine Segments

One of the mostimportantwordsin geometryiscongruent.This term refersto geometricobjectsthat have
exactlythe samesize and shape.Two segmentsare congruentif they havethe samelength.

NotationNotes:

1.Whentwo thingsare congruentwe use the symbol. For exampleif is congruentto , then

we wouldwrite.

2. Whenwe drawcongruentsegments,we use tic marksto showthat two segmentsare congruent.