# what name for a shape made from two intersecting circles of different sizes?

what is the name of a shape made from two circles with different radii that intersect each other?

Sort of like a snowman shape, made of a big and a small ball of snow, melted together a bit! :-) Thanks

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May I hazard a guess? ... Snowman? –  Raskolnikov Apr 29 '11 at 20:19
One interrogation and one exclamation symbol are more than enough. –  Arturo Magidin Apr 29 '11 at 20:20
While a snowman from the West would be the intersection of three circles, the shape you describe is the silhouette of a Japanese snowman. –  buruzaemon Apr 29 '11 at 22:15
Don't you mean union? –  quanta Apr 29 '11 at 23:17

## 1 Answer

I do know that a "figure 8" shape is known as a lemniscate: you can read more here: http://en.wikipedia.org/wiki/Lemniscate. But I'm not sure if that's what you're looking for. What you seem to describe is the union of two circles (of different size) which intersect at two points.

Wikipedia has an interesting "taxonomy" of various shapes and variations of familiar shapes, etc.: http://en.wikipedia.org/wiki/List_of_geometric_shapes

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+1 for the list of geometric shapes. –  Arjang Apr 30 '11 at 0:02
FWIW: the (usual) lemniscate (Bernoulli, Gerono) is not a union of two circles. One can however specialize the hippopede $r^2=4b(a-b\sin^2\theta)$ to the case $a=b$... –  Ｊ. Ｍ. Apr 30 '11 at 0:16
@J.M. No, no. Of course the usual lemniscate is not a union of two circles. I was simply giving the closest approximation I could think of ("figure 8"). But good to make explicit. Thanks. –  amWhy Apr 30 '11 at 0:36
Thank you Amy for your help, that wasn't quite what I was after, but it was nice to get a friendly reply :-) –  lucy May 1 '11 at 10:00
Nice old answer! –  Sami Ben Romdhane Jan 1 at 15:15