What is "in circle o?

In circle O, key concepts revolve around the circle's properties and its relationship with various geometric elements. Here's a breakdown:

• Center: The center of the circle (point O) is equidistant from all points on the circle.

• Radius: A line segment from the center to any point on the circle. All radii of a given circle are congruent.

• Diameter: A line segment passing through the center and connecting two points on the circle. Its length is twice the radius.

• Chord: A line segment connecting two points on the circle. The diameter is the longest chord of the circle.

• Circumference: The distance around the circle, calculated as 2πr (where r is the radius) or πd (where d is the diameter).

• Area: The space enclosed by the circle, calculated as πr².

• Tangent: A line that touches the circle at exactly one point (the point of tangency). The radius drawn to the point of tangency is perpendicular to the tangent line.

• Secant: A line that intersects the circle at two points.

• Arc: A portion of the circle's circumference. Arcs are classified as major arcs (greater than 180°), minor arcs (less than 180°), and semicircles (equal to 180°).

• Central%20Angle: An angle whose vertex is the center of the circle. The measure of a central angle is equal to the measure of its intercepted arc.

• Inscribed%20Angle: An angle whose vertex lies on the circle and whose sides are chords of the circle. The measure of an inscribed angle is half the measure of its intercepted arc.

• Sector: A region bounded by two radii and an arc of the circle.

• Segment: A region bounded by a chord and an arc of the circle.

These elements and their relationships are fundamental to understanding and solving geometric problems involving circles.