Rotate from outside corner to align inside edge

SketchUp
1

I’ve come across this issue several times now, and I’m wondering if anyone has a solution. This specific example is for a truss, but there are other cases where it applies.

As in the animation, I need to rotate on point A, and align the bottom edge of the board to point B. The only other information is that the board is 3.5" wide.

alignment

2

You can use the Pie or the Arc tool to create a guide to make this easy.

3

Oh snap, I knew it would be something simple! (kicking myself)

Thanks!