CK12 - Geometry

Lookat the diagrambelow.

Supposewe’regiventhat.

We know ,since

Hereare someotherproportionsthat mustalso be true by corollaries1-3.

Two AdditionalCorollariesto the CrossMultiplicationTheorem

Herewe havetwo morecorollariesto the CrossMultiplicationTheorem.The “if” part of thesetheoremsis
the sameas above.So the givenin eachproofremainsthe sametoo.

Corollary4:If , , , and , and , then

.

Proof.

Statement Reason

1. Given


2. , , , and , and


3. 
   
   
   
   2. CrossMultiplicationTheorem
   
   
   
   


4. DistributiveProperty


5.