In some real-world settings, taxicab geometry is more convenient, and more relevant, than Euclidean geometry. Engineers use ...

It is a perfect 90°, which is often shown by a small square drawn in between the two lines An obtuse angle is an angle that is bigger than 90° degrees, but doesn’t reach a straight line at 180°.

Anyone flying above rich agriculture regions like those of the American Midwest gets an immediate lesson in Euclidian geometry. Fields are laid out in a perfect patchwork of straight lines and ...

solid geometry of straight lines, planes and polyhedra, and with the mensuration of prisms, pyramids, cones and spheres.

But he does not in his letter refer to what seems to me the chief reason for it, which is that the elementary geometry of straight lines and angles should precede the geometry of plane surfaces ...