Definitions
Chord - A line segment with both endpoints on a circle
Central Angle - An angle formed by two radii of a circle
Inscribed angle - An angle formed by two chords that share a common endpoint
Arc (of a circle) - a portion of the circumference
Central Angle - An angle formed by two radii of a circle
Inscribed angle - An angle formed by two chords that share a common endpoint
Arc (of a circle) - a portion of the circumference
Inscribed Angles: The inscribed angles substended by the same arc are congruent.
Key Ideas
- Inscribed angles sustended by the same arc of a circle are equal
- A central angle is twice the measure of an inscribed angle substended by the same arc
- An inscribed angle is one half the measure of a central angle substended by the same arc
- When the inscribed angle is substended by a diameter of the circle, the inscribed angle is equal to 90°