Meridians of longitude on a globe, 90 degrees apart?There's a video out there somewhere about a design team being asked for a product with two parallel lines joining at right angles
I'm currently in the process of having a new swimming pool built. I'm going to send this to the architect, the engineer and the constructor. The architect wants to design the whole garden with expensive Italian tiles, palm trees and carvings from a local artist, to his design not mine, the engineer wants to place it where he has to do the minimum of structural calculations (its a fixed fee) but it's not where I want it, the constructor wants to sell me extra filtration, larger pumps and extra drainage. F*** me - its a 5 x 3 metre dip pool!
OK, so long as the parallel lines don't have to join each other!Meridians of longitude on a globe, 90 degrees apart?
All parallel lines join at infinity. But who has been there to see if they join at right angles?There's a video out there somewhere about a design team being asked for a product with two parallel lines joining at right angles
But they do - at the poles. Spherical geometry, not planar.OK, so long as the parallel lines don't have to join each other!
Which parallel lines are these? Do you mean the 90th parallel, which is just a point at the pole(s)? Lines of longitude are not parallel and not called parallels, only lines of latitude. See 90th parallel - WikipediaBut they do - at the poles. Spherical geometry, not planar.
Infinitesimally, yes! Not convinced that is a sufficient condition, though...Aren't lines of longitude parallel when they cross the equator?
.... which is why I referred to them as meridians in my post #5, which was a light-hearted attempt to show the funny things that can happen when you try and apply concepts from Euclidian geometry to non-Euclidian surfaces.Which parallel lines are these? Do you mean the 90th parallel, which is just a point at the pole(s)? Lines of longitude are not parallel and not called parallels, only lines of latitude. See 90th parallel - Wikipedia