angle wanted, 2 quarter-circles (2023 Novosibirsk Oral Geo Oly 9.6)
Source:
September 5, 2023
geometryangle
Problem Statement
Two quarter-circles touch as shown. Find the angle .
https://cdn.artofproblemsolving.com/attachments/b/4/e70d5d69e46d6d40368f143cb83cf10b7d6d98.png