This screen clip, on Google Drive, shows how the smart calculator mis-calculates an angle. The value calculated by DraftSight in dimensioning the angle checks when compared with the OS calculator (and a Casio fx-9750G PLUS calculator). The smart calculator differs by around 1 minute 17seconds – Significantly different.
If the second acute angle is calculated and summed with the first a total error (compared with the expected 90 degrees sum) is around 2 minutes 11 seconds. Something certainly appears wrong here.

This seems to be more than just a rounding error because the difference between using 1.3333333333333333333333333333333 (OS calculator) and 1.33333 (smart calculator) as the starting tangent value is only .25 seconds (to 2 decimal places) of angle.

Could this relate to the radians to degrees conversion that has to be done with the smart calculator?

22 Jul 2012, 16:15 (NZ standard time)
[User of DS (Free) V1R2.1 on Windows 7 Home Premium.]