language, math, photography

Perpendicular: Upright or Uptight?

Calling 90 degrees a “right” angle is a little misleading.  Yes, spatial coordinates should usually be based on perpendicular lines.  But 90 degrees is often just one among many, and perpendicular may not be right for the job.
(BTW, the [Menu] button atop the vertical black bar reveals the widgets.)

Perpendicular ~ Pic and a Word Challenge #269

The ceiling should be perpendicular to the wall
(and the wall to the floor).


Even the klutz who built my house got that right.



The right angle for slicing a pizza depends on
how many slices are needed.


© sabelnik | 123RF Stock Photo


Willing to count a circle as a “line” perpendicular to any chosen straight line thru the center?  (I am.)  If so, then spatial coordinates should almost always (not just usually) be based on perpendicular lines.  Want to navigate on a really big pizza?  Use polar coordinates.