Bless all of you who get involved with classroom teaching. One of the best group activities I ever did was with staircases. Angles, Pythagorean Theore...

The words "based on" in the description create some doubt. NCDOT uses that term to describe "ground coordinates" derived by some transformation applie...

@bill93 Seems like you did something with linear regression and Lambert to TM points. It was pretty good math.

@bill93 The exercise was indeed rigged to make the point. Doesn't at least some field software assume a Transverse Mercator projection for 5000, 5000...

@rover83 It's easy to forget that the coordinate systems are just sophisticated models of the real world. But losing sight of either their sophistica...

@goodgps i see. I don't have the software to do this, but perhaps you will take a couple of minutes to do it. Consider these 4 NGS points in North C...

I know nothing about the software, but the words "erroneous coord system" are worrisome. GIGO (Garbage In, Garbage Out) is always operative.

Just uninformed blind searching in Google turned this up. Probably not what you're looking for, but maybe interesting in its own right. Also, being la...

@geoff-ashworth I think you've nailed it.

@geoff-ashworth That looks good. The final test is this: are the lengths of the two tangent lines from their intersection to their points of tangency...

@john-nolton Having spent many wee hours deriving test problems, and having published some on tests that weren't solvable, I know that it is a challe...

Point E, the point where the two circles are tangent, can be moved randomly without changing the given information. Here are two cases from Geogebra: ...

?ÿI thought so, too, but I don't see the line in any of the four equations. I think that the line constrains the location and size of the small circle...

@john-nolton So it's a least squares solution and the values are not zeroes of the four equations. We have two adjacent sides of the quadrilateral an...

@john-nolton LOL! Maybe he did it for you and didn't tell you how! 😉 I put Dave's drawing in Geogebra with some of the givens and some eyebal...

@dave-lindell Yes they do. Thanks, Dave.

@john-nolton No credit unless you show your work!

@john-nolton Yes, the opposite triangles are similar. It made sense since the opposite angles in the quadrilateral are supplementary and the sum of t...