If your deck is slightly out of square (different widths), calculate results for both widths, and set out each end to suit.
If necessary, adjust number of deck boards to match in both calculations, and see if different board gaps at each end of deck are acceptable, compared to equal gaps and cutting the last board at an angle.
To fine tune Slider Controls click to select and use ◄► (cursor) keyboard keys.
Your iPad, iPhone or Android Tablet or Phone is a valuable On-Site tool!
Lay your phone or tablet on an angled surface (roof ?) to directly measure angles and automatically calculate Roofing and Pitch Angle Apps.