How do we use the properties of trapezoids

Trapezoids : Exactly one pair of parallel side
Trapezoid Consecutive Angles Conjecture: the consecutive angle between the bases of a trapezoid
isosceles Trapezoid conjecture: The base angle of a isosceles trapezoid 

 for more help check out the links below

• http://www.youtube.com/watch?v=jKwY4OjfMS4
• http://www.cliffsnotes.com/study_guide/Properties-of-Trapezoids.topicArticleId-18851,articleId-18798.html
• http://www.coolmath.com/reference/trapezoids.html
• http://www.youtube.com/watch?v=fR_ctVqueo4