Main Ridge
and
Dormer Ridge
intercept in
Plan View = 90°
Purlin Face
perpendicular to
Dormer Roof
Saw Blade Bevel = arcsin (cos Main Roof Pitch Angle × sin Dormer Pitch Angle)
Saw Blade Miter = arctan (cos Dormer Pitch Angle ÷ tan Main Roof Pitch Angle)
Angle on the Stick = arctan (tan Main Roof Pitch Angle ÷ cos Dormer Pitch Angle)

Purlin Face
set in
Dormer Roof
Saw Blade Bevel = arcsin (cos Main Pitch Angle × cos Dormer Pitch Angle)
Saw Blade Miter = arctan (sin Dormer Pitch Angle ÷ tan Main Pitch Angle)
Angle on the Stick = arctan (tan Main Pitch Angle ÷ sin Dormer Pitch Angle)

