Proposition 34
Construction
To cut off from a given circle a segment which contains an angle equal to a given angle.
ἀπὸ τοῦ δοθέντος κύκλου τμῆμα ἀϕϵλϵῖν δϵχόμϵνον γωνίαν ἴσην τῇ δοθϵίσῃ γωνίᾳ ϵὐθυγράμμῳ.
From a given circle to cut off a segment admitting an angle equal to a given rectilinear angle.