Naming Concentric Circles: What's the Best Approach?

[faiz4000]

how do you name a circle? Obviously you could name it by its centre example a circle with centre at O would be called circle O. but what if you have two concentric circles?

 

[enthropy]

Knowing the radii, you could say the circle centered at O with radius r

 

[faiz4000]

it seems an odd way to name figures. for other things we use a set of points to name other types of figures. for example, quadrilateral ABCD. shouldn't the circle be named like that too?

 

[enthropy]

Polygons have vertices, which is why they can be named using the vertices' names. This is the same as naming a circle by it's center, but that doesn't allow for uniquely naming concentric circles.

 

[faiz4000]

yes, but there must be unified way that works in all situations. does somebody know the conventional rule written somewhere for the purpose?? your method of using the radius seems OK but do you know that its the proper way?

 

[enthropy]

Circles don't have vertices, so that system can't apply. The center and radius system is how everyone I know does it, including the federally-mandated curriculum.