1) The document is the first chapter on circles from a 10th grade mathematics textbook. It reviews basic circle terms like secant, chord, segment, and sector.
2) A secant is a line that intersects a circle at two or more points. A chord is a line segment whose endpoints both lie on a circle. A segment is the region bounded by a chord and the arc subtended by the chord. A sector is a portion of a circle made of its arc and two radii.
3) A tangent is a line that touches a circle at exactly one point on the outside of the circle. At the point of tangency, the tangent line is perpendicular to the radius. Tangent segments