The points A, B, C, D, E lie on the circle with center F, and EB is a diameter. The central angles around F must sum to 360°.
The given central angles are:
∠AFB=90°,∠BFC=18°,∠CFD=108°
The remaining central angles satisfy:
∠DFE+∠EFA=360°−90°−18°−108°=144°
The arc DEA⌢ (from D to E to A, not passing through B or C) corresponds to the sum of central angles ∠DFE+∠EFA:
DEA⌢=144°
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