Complementary or Supplementary?

Date: 04/02/2001 at 16:25:51
From: Brianne Lorom
Subject: Supplementary/Complementary

I don't get what complementary and supplementary mean.  I keep getting 
them mixed up.  How can I remember which is which?

Date: 04/02/2001 at 16:42:54
From: Doctor Peterson
Subject: Re: Supplementary/Complementary

Hi, Brianne.

In our archives we have an explanation of the origin of the terms 
complementary and supplementary, which shows that there's really no 
reason why they should have the specific meanings they do:

  Complementary and Supplementary Angles
  http://mathforum.org/dr.math/problems/saunders9.30.98.html   

That means there's no good clue in the words themselves. The best way 
I've come up with to remember the difference is that the words are in 
alphabetical order. Complements add up to 90 degrees, and supplements 
(later in the alphabet) add up to 180 degrees (which is larger). You 
might also associate "s" with "straight" and "c" with "corner." 

Whatever trick you remember easily is okay!

- Doctor Peterson, The Math Forum
  http://mathforum.org/dr.math/