Circle Stuff Notes Flashcards
What is a Circle?
The set of all points equidistant from a centerpoint
What is the Centerpoint and what is the label of it?
It is the center of a circle and is labeled with a capital C
What is the radius?
A segment that connects the center to any point on the circle.
What is the Chord?
A segment whose endpoints are on the circle.
What is the diameter?
A chord that goes through the center of the circle.
What is the Secant?
A line that intersects a circle at two points
What is the Tangent?
A line that intersects a circle at one point.
What is the area of a circle formula?
A=πr2
How do you label a circle?
(.) and the letter
If you have a minor arc, and you move the angle of the arc further away from the points, what happens to the angle?
The further away the arc is from the points, the lesser the angle.
What is an arc?
A part of a circle whose measure is equal to the corresponding angle (central angle).
What is the central angle?
An angle whose vertex is on the center of the circle.
What is the minor arc
An arc whose measure is less than 180 degrees. The measure of the arc is equal to the central angle that intercepts it.
What is the major arc?
An arc whose measure is more than 180 degrees
What is the Semicircle?
Half of a circle; an arc whose measure is exactly 180 degrees; has to be made up of 3 points
How many points should you name for a minor arc on a circle?
2 points (only the ones on the edge)
How many points should you name for a major arc on a circle?
3 points (1st point, random point along the arc, 3rd/endpoint)
How do you label an arc?
With an upside down line (arced line)
How do you label a semi-circle?
Same as a major arc: 3 points (1st point, random point along the arc, 3rd/endpoint)
What is an inscribed angle?
Angle whose vertex is on a circle and whose sides contain chords of a circle
What is intercepted arc?
Arc between two sides and the inscribed angle
What does subtend refer to?
intercepted arcs subtend the inscribed angle
What happens if two or more inscribed angles of a circle intercept the same arc?
The angles are congruent.
What happens if an inscribed angle intercepts a semicircle?
The inscribed angle is 90 degrees
If all the vertices of a quadrilateral are inscribed/on the circle, then what does this mean?
Opposite angles are supplementary (180)
What is an inscribed angle?
An angle whose vertex is “on” the circle
What is an Interior angle?
An angle whose vertex is in the interior of a circle
What is an exterior angle?
An angle whose vertex is in the exterior of a circle
What is the formula for a central angle?
Angle=Arc
What is the formula for an inscribed angle?
Angle=1/2 times the arc
What is the formula for an interior angle?
1/2(2 arcs added together)
What is the formula for an exterior angle?
1/2(difference of both arcs)
