Two of these polygons are the subjects of Pedoe's inequality, for which equality obtains only when the two polygons are similar. The unique ellipse that can be inscribed in on
Two of these polygons are the subjects of Pedoe's inequality, for which equality obtains only when the two polygons are similar. The unique ellipse that can be inscribed in one of these polygons is named for Jakob Steiner. Their side lengths are related to the length of another line segment by (*) Stewart's theorem, while a theorem giving a concurrency condition for certain lines in this shape is named for Giovanni Ceva. The area of this polygon is given by Hero's formula, and the laws of sines and cosines describe this kind of shape. For 10 points, name this polygon whose interior angles sum to one hundred eighty degrees and that has three sides.
Two of these polygons are the subjects of Pedoe's inequality, for which equality obtains only when the two polygons are similar.
{triangles} [accept {three}-{sided polygon} or other equivalent complete definitions before mention]