Gregory's Server@salgood Those angles are only 90 degrees at an infintesimally small point where the line meets the curve so you could argue they dont exist
|
6 comments
 @erwinrossen @salgood I always saw it as the intersection of 2 vcetors but I guess youre right @RavenLuni @erwinrossen @salgood i think this is drawn using a polar coordinate space rather than a Cartesian space. In a polar sense, the lines are all either moving longitudinally or laterally, so the 90 degree rule checks out.  @RavenLuni @erwinrossen @salgood a square is also defined as the opposing lines have to be parallel. (As they are a subbody of a parallelogram) @NafiTheBear @RavenLuni @erwinrossen @salgood Common definitions also include that the diagonals intersect at a set of right angles too. @erwinrossen @RavenLuni @salgood More formally, the angle between two smooth curves at a point is defined to be the angle between the tangent lines at that point. A bigger problem with the image is that when you talk about some figure made up of arcs, you should always measure your angles on the same side (inside or outside): really the shape shown has two 90 degree angles and two 270 degree angles. |
@RavenLuni @salgood Well, that's the definition of an angle, right? An infinitesimal distance away, there is no angle anymore.