Cannot Explain a SketchUp Dimension Result

In drawing an example of how a center finder works, I drew a right triangle with an hypoteneuse of 6" and an altitude of 5.5". The Pythagorian Theorem says that the third leg should conform to the formula, (aa) + (bb) = (c*c). I’ve done the math in a calculator program and got he result, 2.3979"; however, SU gives a dimension of 2.4260" for a difference of 0.0281."

Now, that is close enough among friends, but I don’t understand the discrepancy. The attached file shows the results. You will notice that the hypoteneuse length is actually 6.0001" in SU, but one ten-thousandth of an inch shouldn’t cause a difference of that magnitude (or ‘minitude’ :sunglasses:).

I suspect that there is an error in my drawing that I cannot discover. I would appreciate extra eyes looking at the drawing and/or an explanation of the error. On a scale of inches, it really isn’t significant; but it certainly would be with a much larger scale.


Error.skp (143.4 KB)

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The problem is your “right triangle” is ~89.710°

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Thanks, Geo!

I thought I checked it but must not have. I did use the inference lines when drawing it. Shouldn’t have been so careless.

Another case of not being able to see the forest for the trees.

Much obliged!


The Rectangle tool always draws perfect right angles.
And the Arc tool that draws from center and two points is handy for laying out the hypotenuse.
Error_Fixed.skp (23.7 KB)

I once had a concrete mason who couldn’t see the end of his 100’ tape measure.
Reason being, the tip broke off, so he cut it off ‘precisely’ at 1’-0"
With that, he carried on laying out a home foundation w/ attached garage.

Then it came time to frame the building.
While the diagonals of each were equal, I found the front walls of house and garage weren’t parallel.
That’s when it came to light the rear wall of the garage was a foot short !!

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