The angles which intercept arcs are :-

∠ AOB

∠ BOC

∠ COA

In arc AXB

Point A, B are on arms AO & BO

∠ AOB is intercept of arc AXB

In arc BYC

Point B, C are on arms BO & CO

∠ BOC is intercept of arc BYC

In arc CZA

Point C,A are on arms CO & AO

∠ COA is intercept of arc CZA