Cube Edges

Date: 04/01/97 at 21:26:24
From: Tyler Hope 
Subject: Cube Edges

How many edges does a cube have? My dad says that there are six edges 
on a cube, but I think there are twelve edges. I know that a cube has 
six sides,  but edges and sides are not the same.

Date: 04/02/97 at 00:19:42
From: Doctor Steven
Subject: Re: Cube Edges

There are 8 vertices on a cube, and 6 faces, so there are 12 edges or 
lines connecting one vertex to another, on a cube.

There are eight vertices because you have one square on the bottom 
and another square above it and you connect the two squares with edges 
to form a cube.  Note that the bottom and top squares both have four 
edges, so to connect the squares you must add four more, one at each 
of the corners. This makes 12 edges in total. 

The top and bottom squares make two faces and when you add the four 
new lines you add 4 more faces, for a total of 6 faces.

Hope this helps.

-Doctor Steven,  The Math Forum
 Check out our web site!  http://mathforum.org/dr.math/   

Date: 04/16/97 at 00:19:42
From: Doctor Chuck

It is often hard to see these problems in your mind. Whenever I 
have trouble visualizing a three-dimensional object, I find that the 
best thing I can do is grab some play-dough or clay and MAKE the 
object so that I can poke and prod at it. 

So, a good way to solve your problem is to find a box (like a shoebox 
or a cereal box, which is a stretched cube), take a marker pen, and 
number each of the edges. The beauty of this is that you don't just 
convince yourself that a box (like a cube) has 12 edges, you also can 
show this box to your father and convince him, too.

-Doctor Chuck,  The Math Forum
 Check out our web site!  http://mathforum.org/dr.math/