Miter/Bevel angle

[ufg8r85]

I wish to install a box fan in the corner of my garage near the ceiling. I'm thinking of putting a 2x4 or so across the corner, but I also want it angled down at 45 degrees. I'll then mount the fan to this, along with a piece from the ceiling to keep the fan in place.
What miter/bevel angle should I make these cuts? 45 and 45 didn't work,is there a formula?...

As always, thanks in advance,

Steve

[LCHIEN]

I wish to install a box fan in the corner of my garage near the ceiling. I'm thinking of putting a 2x4 or so across the corner, but I also want it angled down at 45 degrees. I'll then mount the fan to this, along with a piece from the ceiling to keep the fan in place.
What miter/bevel angle should I make these cuts? 45 and 45 didn't work,is there a formula?...

As always, thanks in advance,

Steve

You can just make a compound cut and then you don't have to measure.
Set the saw to make a 45 degree miter cut, then also tilt the saw (bevel) angle 45 degrees. and make the cut.

You can do this with either table saw or a compound miter saw.