There are several video tutorials on Sketch and Line’s Multi-Touch gestures. Of course, Sketch’s big draw (no pun intended) is its pairing with Adobe’s new Ink and Slide stylus tools.

Now we have colonized great swaths of the planet (and even the skies) with our geometry of straight lines. In the long run it is not at all clear if it was a good idea.

The remaining chapters deal with the pure geometry of triangles and circles, solid geometry of straight lines, planes and polyhedra, and with the mensuration of prisms, pyramids, cones and spheres ...

I QUITE agree with Prof. Alfred Lodge as to the order of propositions he proposes, which is practically the order I adopted in my “Foundations of Geometry.” But he does not in his letter refer ...

A straight line angle equals 180º. To find the sum of the two angles, add them together. Then, we subtract this from 360º. ... Drawing and measuring angles. count. 7 of 8. Angles in polygons. count.