GRE Math : Diagonals of a Regular Octagon
Part of your preparation involves knowing what all these math terms mean. So let’s talk about octagons in particular and diagonals in general. An octagon is an eight-sided polygon, which contains either vertices. A vertex is the place where two lines meet, represented by letters on the octagon below.
An “adjacent” vertex is one you could get to by walking along one side of the octagon. For example, if we start at vertex A, the only two adjacent vertices are B & H. Those are the two vertices we could reach from A walking directly along the side of the octagon.
A diagonal of any polygon is a line through the middle of a polygon. A fancy way to say “any line segment connecting two nonadjacent vertices.” Well, starting at vertex A, B & H are the adjacent vertices, so C & D & E & F & G are the “nonadjacent” vertices—a straight line from any of those would not be along the side but rather would “cut through” the center of the octagon—in others, those five lines (shown in green) are diagonals.
Obviously, a line segment connecting two adjacent vertices can’t be a diagonal because it’s a side: AB and AH are sides of the octagon, while AC, AD, AE, AF, and AG are diagonals.
0 comments :
Post a Comment