Triangle Formula Cheat Sheet

[Ian Wilson]

I'm teaching Engineering Surveying for the ASCE Chapter in Sacramento again.

Just recently, I saw a two sheet "cheat sheet" of triangle formulae that were written in a circle around a triangle.

I thought I saw them on this site as an attachment. I could have sworn it was an attachment from Paul Plutae.

Does anyone know what I'm talking about and can anyone point me to the sheets or send them to me, please.

Thanks in advance!

[Ian Wilson]

And here they are...courtesy of Surveyor Connect..

[Ian Wilson]

And...

[PLS7393]

Never seen these before Ian, thanks.
I sure could have used these back in my student days.

[E_Page]

That's pretty novel. A pretty useful way of putting all those combinations together.

[land butcher]

Pretty slick

[LS_8750]

Cute. Never seen it before.
Devised by Ivy League scared c average trig student in the 1930s likely, that discovered a way to make a buck.

Too many formulas will spoil a clear thought process. I've never encountered a reason to remember any of that stuff. COGO (when you know the definition) trumps all silly trig and geometry. Well, at least when you've mastered geo and trig. Y = mx +b trumps trig every time. Of course, only when you know the facts.

[bruce hall]

thought that the sine of half delta multiplied by twice the radius was a slick formula to get the chord.

Another one was decimal degrees multiplied by the radius multiplied by 0.01745329 to get the arc length.

Not sure about Y

[Dave Karoly, PLS]

Pie are round, not square.

[Dave Lindell]

The trick is...can you derive them?