Discussion:  All Topics in Geometry 
Topic:  Is a rhombus a kite? 
Post a new topic to the All Content in Geometry discussion 

Subject:  RE: Is a rhombus a kite? 
Author:  LFS 
Date:  Apr 21 2008 
and
As far as I have been able to tell  we don't talk about "kites" but rather
"deltoids" and a deltoid by definition is a quadrilateral with two pairs of
congruent adjacent sides (whether or not distinct depends on the book...).
My question: Does the "standard" definition of quadrilateral assume
convexness?
I have the impression that the definition of a kite assumes convexness.
All definitions of polygons assume "simple", i.e. nonintersecting sides, but
not convex.
On the other hand, everywhere I found the definition of a quadrilateral to be: a
foursided polygon.
By having (at least) one pair of nonadjacent parallel sides, parallelgrams
and trapezoids are automatically convex.
But if we allow nonconvex polygons, deltoids would include both kites and
arrowheads. Or maybe a kite can be an arrowhead?
Thanks for any help clearing this up for me.
 
Post a new topic to the All Content in Geometry discussion  