CK12 - Geometry

3. squareinches


4. The -gon


5. cm


6. The -gon

7.

8.

GeometricProbability

LearningObjectives

• Identifyfavorableoutcomesand total outcomes.


• Expressgeometricsituationsin probabilityterms.


• Interpretprobabilitiesin termsof lengthsand areas.

Introduction

You’veprobablystudiedprobabilitybeforenow (pun intended).We’ll start this lessonby reviewingthe basic
conceptsof probability.

Oncewe’vereviewedthe basicideasof probability, we’ll extendthemto situationsthat are representedin
geometricsettings.We focuson probabilitiesthat can be calculatedbasedon lengthsand areas.The for-
mulasyou learnedin earlierlessonswill be very usefulin figuringthesegeometricprobabilities.

BasicProbability

Probabilityis a way to assignspecificnumbersto how likely, or unlikely, an eventis. We needto knowtwo
things:

• the total numberof possibleoutcomesfor an event.Let’s call this.


• 
  

  the numberof “favorable”outcomesfor the event.Let’s call this.

  
  

The probabilityof the event,call it , is the ratio of the numberof favorableoutcomesto the total number
of outcomes.

Definitionof Probability

Example 1