CK12 - Geometry

pointson the line;

Now it’s time to start with the given.Thenwe use logicalreasoningto reachthe statementwe want to prove.
Often(not always)the proofstartswith the giveninformation.

In the two columnformat,Statementsgo on the left side,andReasonsfor eachstatementon the right.
Reasonsare generallydefinitions,postulates,and previouslyprovedstatements(calledtheorems).

Statement Reason

1. Given
   Given


2. , and are collinearin that
   order


3. Reflexive


4. andSegmentAdditionPostulate


5. AdditionPropertyof Equality


6. Substitution

is whatwe weregivento prove,and we’vedoneit.

Example 2

Writea two-columnproofof the following:

• Given: bisects ;


• Prove:

Statement Reason

Given

1. bisects


2. Definitionof anglebisector


3. AngleAdditionPostulate