DIY & Home Improvement

So leave the second board long, and do a 90 degree cut at the final length.

The issue is corners aren't corners. They're actually slightly rounded, because joint compound or plaster builds up in the corner. Which is probably the primary reason that this corner is measuring 95 degrees - the measuring tools are short enough to be greatly affected by the hump of compound/plaster.

In addition, it is extremely unlikely that the wall is straight over anything but a trivial distance. This also makes measuring the corner itself inaccurate.

So make your first cut at approximately 1/2 the angle, and use it to get the angle for the 2nd miter cut. Make a 3rd cut if necessary to get the overall length.