# name of a shape

Let P be a point, not the center, in the interior of a (round) disk D⊂ℝ² and let A and B be points on ∂D such that the line segments AP and BP have equal length. Choose an arc AB. What's the shape bounded by the arc and the two segments called?

• For $P$ at the center, that's a "sector". ( en.wikipedia.org/wiki/Circular_sector ) I don't know of a name for $P$ elsewhere. How about "pseudo-sector" or "generalized sector"? (BTW, this might be a cleaner description: Given P on the diameter bisecting arc AB, the figure bounded by AP, BP, and arc AB.) – Blue Jan 10 '11 at 0:02
• What leads you to believe that this object should have a name? – Tpofofn Jan 10 '11 at 1:07
• I call this a "slice" ;) – Matt Calhoun Jan 10 '11 at 1:25
• @Jasper Loy "By '(round) disk' do you simply mean circle", well, a circle is one-dimensional; I meant the thing it bounds. – msh210 Jan 10 '11 at 16:39
• @Day Late Don "a cleaner description": Yes, thanks! – msh210 Jan 10 '11 at 16:42