# What do you call a shape with a single bend and lines going into infinity?

This question came up on a pub quiz last night. The answer was parabola.

I disagreed, because I thought I remembered that angles could go off into infinity too. An angle is two rays whose endpoints are shared, so would that also count as a "bend" ? Or is there another name for this type of angle?

-
There isn't enough information to answer the question. There are infinitely many types of shapes that look like this, e.g. a catenary: en.wikipedia.org/wiki/Catenary – Qiaochu Yuan Feb 2 '11 at 16:35
I guess my point is is that based on the question it can not just be a parabola as the Quizmaster indicated! – GJTorikian Feb 2 '11 at 16:40
To add to Qiaochu's comment, even a hyperbola is a better answer for two reasons: (a) among conic sections, there are more hyperbolas than parabolas (in the sense that a parabola can be taken as a degenerate limit of a family of hyperbolas) (b) related to the first part is the consideration of the orbit of an object flying in from far away (infinity), approaching the solar system, and flying away again. For such an object it is generally more likely the orbit is hyperbolic than parabolic. – Willie Wong Feb 2 '11 at 16:44