WildTrig5: Applications of rational trigonometry

At time 6.25, how do you determine which solution is correct, besides identifying the figure as "close" to an equilateral triangle?

It is a reasonable question. The other solution would have Q roughly 26, but this is too much, since then the top of the kite would form a triangle with quadrances 4,4,26. If two quadrances are 4, then the maximum possible quadrance for the third side is 4x4=16.

I think there's sign error at 7:15 in this movie. The first 4 in the line below the "In ABC" should be positive, not negative. If I'm right, you could note it in the video description text, or else if you still have the original for editing, you could superimpose text to alert watchers to the typo. (I realize you probably have other stuff to do.)

I don't see that there is an error. The signs are correct. Remember that (A+B-C)^2 is the same as (C-A-B)^2, so the Cross law is written in two slightly different ways sometimes, depending on the situation.

You're right. I should have been watching closer before I posted this as an "error." Sorry.

This great stuff, a nice break from some of youtube's irrational garbage. I really enjoyed this review of some of these euclidean notions. It just wonderful that someone put some pure geometry on youtube rather than one of their "opinions" (I mean to say their ideological positions that have no evidence to back them up).

Keep it coming!

whats this about? we always use SOH CAH TOA