Step 1: Recall Angara Kosha.
Angara Kosha refers to a specific anatomical measurement described in classical Sharir texts
Step 2: Recall the Pramana unit used.
Classical texts measure such structures using body-proportion units like Hasta and Rajahasta rather than fixed modern units
Step 3: Match the classical value.
The Pramana assigned to Angara Kosha in the texts is Rajahasta
\[ \boxed{Rajahasta} \]