9.0 - Circle Basics

Secant

• Line that intersects the circle at two points.

• A line that touches the circle at one point.

• A line that is tangent to the circle.

• A line that is parallel to the radius of the circle.

Circle

• All points that are a fixed distance from the same point.

• All points that are a fixed distance from the same point.

• A shape with four equal sides.

• A line that connects two points.

Radius

• Straight line from the center to any point on the circle.

• The distance around the circle.

• A line segment that connects two points on the circle.

• The area enclosed by the circle.

Central Angle

• An angle whose vertex is at the center of a circle.

• An angle formed by two tangents to a circle.

• An angle whose vertex is on the circumference of a circle.

• An angle that measures more than 180 degrees.

Tangent

• Line that touches the circle at exactly one point, called the point of tangency.

• Line that touches the circle at exactly one point, called the point of tangency.

• Line that is parallel to the radius of the circle.

• Line that passes through the center of the circle.

Arc

• Part of a circle connecting two points.

• A straight line between two points.

• A segment of a triangle.

• A type of polygon with three sides.

Semi Circle

• Arc whose endpoints form a diameter.

  Equal to 180 degrees.

• A full circle divided into two equal parts.

• A shape with three equal sides.

• A line segment connecting two points on a circle.

Minor Arc

• Arc whose measure is less than 180 degrees.

  Only use two letters to name.

• Arc whose measure is exactly 180 degrees.

• Arc that is larger than a semicircle.

• Arc that cannot be named with two letters.

Inscribed Angle

• Angle whose vertex is on the circle.

• Angle formed by two chords in a circle.

• Angle whose vertex is outside the circle.

• Angle formed by a tangent and a chord.

Chord

• Segment whose endpoints lie on the circle.

• A line that intersects a circle at two points.

• A line that touches a circle at one point.

• A segment that connects the center of the circle to a point on the circle.