Small challenge

[Pekis]

(06-07-2017 10:53 PM)SlideRule Wrote:  Pekis

I used the Line-Circle intersect equations to calculate the coordinates of point D & since the other points can all be derived by rotating the line segment thru points O & B to align with the y axis, the rest is simple trigonometry / geometry using the distance formula, etc.

I've attached a grahpmatica screen capture to illustrate the deviation in the two Arcs thru pts C-D created by the two segments C-A-D (with central angle @ A) & C-O-D (with central angle @ O). The approximate delta is 0.0235.



BEST!
SlideRule

edit: found and corrected numeric typo - omitted a digit!

But there is no arc with central angle at A ! The only existing arc is created by outer circle with radius r and points C and D, with central angle at O, and for which I used the arc height formula.
Another completely different thing is the equilateral triangle ACD ... But I understand it can be confusing