And the angle in a segment is the angle contained by the joined straight lines, when any point is taken on the circumference of a segment, and straight lines are joined from it to the ends of the straight line which is the base of the segment.
An inscribed angle is the angle $\alpha$ contained by the straight lines joining the ends of the arc $AB$ with any point on the circumference of a segment of the circle.
Definitions: 1
Proofs: 2 3 4 5 6 7 8
Propositions: 9 10 11 12 13 14 15
Sections: 16