What is a trapezoid, and who created it?

since I am a optics scientist, you know, the most key device for optics is grating, especially rectangular grating. read more

A tangential trapezoid is a trapezoid that has an incircle. A Saccheri quadrilateral is similar to a trapezoid in the hyperbolic plane, with two adjacent right angles, while it is a rectangle in the Euclidean plane. read more

since I am a optics scientist, you know, the most key device for optics is grating, especially rectangular grating. However, in actual fabrication process, the line is right straight, so we can only fabricate a trapezoid grating, maybe best High-tech can make a infinity to a rectangular grating, but still a trapezoid grating. read more

A trapezoid: has a pair of parallel sides is an Isosceles trapezoid when both angles coming from a parallel side are equal, and the sides that aren't parallel are equal in length. read more