Trèteaux Angles: P23a-DP
 P23a-DP = Adjacent Side (Foot Cut) for Rotated Purlin Rafter Miter Angle on DP Side Of Hip Rafter on Face Perpendicular To Roof Surface, Lower Claw Angle
 Hip-Valley Roof Ratios Angle Formulas
- P23a-DP = arctan( sin (P22a ) ×  tan ( 90 - Valley Sleeper Saw Blade Bevel Angle ))
- P23a-DP = arctan( sin (P22a ) ×  tan ( 90 - VSB )) 
 
 
 
 
The Trèteaux Angles Formulas for Hip Rafters Rotated into the Roof Surface Plane were developed by Sim Ayers and Joe Bartok.