See if you can bring construction and calculation together in forrowing example and compare the results:
on my iPhone I make it:
8426.149773176359
Its the square root of 71 million.
Interestingly Excel says thats exactly 8426.149773176300000000
But my phone says 8426.149773176359 which is strange
Sorry @DaveR, unfortunately your construction is off. Did you use the āPieā tool? That should give you a different value if applied correctly.
Calculation somewhere along the line shows that the length is sqrt(71). Boosts my trust in SketchUp.
Apply the āPieā tool on A-B
No. I didnāt use the Pie tool.
That probably explains the difference.
I didnāt see any reason to use the Pie tool. It was a simple enough construction without it. But nevermind.
The āPieā tool (and the āArcā tool) provides a true arc intersection. The āCircleā tool still uses a segmented circle.
Sorry - but I still cant get that to work.
What length did you set the Pie Tool radius to?
It should be sqrt of 80M = 8944.271909999159
I didnāt set the radius in āEntity Infoā toā¦ other than using the dotted edge A-B (see image above) as the radius for the āPieā tool. Rotate this edge about A to get the pieās intersection with the horizontal edge (which was larger to begin with).
I get 8,426.1497731763586306341399062027.
Continue the calculation to the end ā sqrt(71)
If somewhere in the middle of the proces you input value like 8944.271909999159, SketchUpās āEntity Infoā might round the input. Either calculate all te way through or be lazy and let SketchUp help you.
Yes - I tried that method as well but I cannot get the exact figure you are showing. I am always a few tenths or sometimes a few hundredths off. Also my pie radius is definitely segmented - I wonder if there is there a setting somewhere that makes it a true radius?
ā¦2027 should be ā¦2327 
I canāt get the Pie tool to find the exact intersection of two arcs - it will snap to the segments instead. The figure could be at any angle, it is not given that the line with the length to be determined is horizontal.
See the 90 degrees angles in the first image.
I think you only need one arc.
The line with the length to be determined is at right angles to the 3000mm vertical line.
The hypotonuse is sqrt 80M = 8944.271909999159 +/- but I cannot get that radius to intersect the horizontal line and give the AB line length accurately?
Youāll need to wait till you see the intersection cross (red near āFrom Pointā)
@Anssi, only one arc can be handled as true arc at a given time. But then only one (āPieā) is needed to intersect the horizontal edge.
I hope you didnāt miss the right angle in the upper left corner.
Even with 64-bit numbers, you generally can only get 16-17 significant figures in base 10. Excel limits these to 15 sig-figs.