CK12 - Geometry

This proofis very similarto the previousproof,and it also relieson isoscelestriangleproperties.

Statement Reason

1. Given


2. Trapezoid has and


3. ParallelPostulate


4. Construct


5. 
   
   
   
   3. CorrespondingAnglesPostulate
   
   
   
   


6. is a parallelogram 4. Definitionof a parallelogram


7. 
   
   
   
   5. Oppositesidesof a parallelogramare
   
   
   
   

Trapezoid with auxiliarylines

6. 
   
   
   
   6. TransitiveProperty
   
   
   7. Definitionof isoscelestriangle
   
   
   
   


7. is isosceles


8. 
   
   
   
   8. Converseof the BaseAnglesTheorem
   
   
   
   


9. 
   
   
   
   9. TransitiveProperty
   
   
   
   

Example 2

Whatis the lengthof in the trapezoidbelow?