Vocabulary
An Arc
The portion of a circle in between two points.
Three questions to consider before solving a central angle question
1. Is there a diameter?
2. Are there vertical angles?
3. Is there a whole circle?
Inscribed Angles
Angles with an half arc that touches the edge of the circle.
Interior Angle Theorem
The measure of the angle formed is equal to 1/2 the sum of the intercepted areas.
Exterior Angle
An angle considered to be outside of a circle if the vertex of the angle is outside the circle and the sides are tangents or secants.
Arc Length
The distance traveled between the two points on the arc.
Central Angle Theorem
The measure of the center angle is equal to its arc.
What do you do if you are given the arc?
Divide by 2
How many levels of problem solving is there for interior angles?
4
Exterior Angle Theorem
The measure of the angle formed is equal to 1/2 the difference of the intercepted arcs.
Diameter
A chord passing through the center of the circle.
Central Angle
An angle whose vertex lies on the center of the circle.
What do you do if you are given the angle?
Multiply by 2
Interior Angle
An angle considered inside a circle when the vertex is somewhere inside the circle, but not on the center.
What do you do if you have two tangents?
Subtract from 360
A Tangent
A line outside the circle that only intersects the circle at the point of tangency.
What do you subtract from if the circle has a diameter?
180
Corollary
If two inscribed angles intercept the same arc, then the angles are congruent.
All angles inside a circle are formed by two intersecting chords (True or False)
True
What are the x and y of exterior angle problems called?
x= Major
y= Minor
Secant
A line on line segment that begins outside the circle, passes through one side of the circle and ends at the other side of the circle.
What do you subtract from if the circle is a whole circle?
360
What type of angle is an angle inscribed in a semicircle?
A Right Angle
What would a level 3 interior angle problem setup look like?
2x-7= 92+86/2
What is the setup for an exterior angle problem?
x-y/2