Circle Vocabulary and Central Angles

Unit 8: Circles

8.3 Circle Vocabulary 2

Multiple Choice

The distance from the center of a circle to the boundary of a circle (half of the diameter).

• Chord

• Diameter

• Radius

• Inscribed Angle

Multiple Choice

A segment/chord that runs through the center of the circle (the longest chord).

• Chord

• Diameter

• Radius

• Inscribed Angle

Multiple Choice

This formula is used to find what?

• Area

• Circumference

Multiple Choice

This formula is used to find what?

• Circumference

• Area

Multiple Choice

If the radius of a circle is 6 what is the area?

• 6π

• 36π

• 12π

• 24π

A segment with endpoints on the circle. (Diameters are just one kind of chord.)

1. Chord

A line that intersects (passes through) the circle in two places.

2. Secant

A line that intersects the circle at just one point.

3. Tangent

Dropdown

Line EB is a ​

Select answer

.

Dropdown

Line AB is a ​

Select answer

.

Dropdown

Line CD is a ​

Select answer

.

The point at which the tangent line intersects the circle.

4. Point of Tangency

An angle inside the circle whose vertex is the center and two sides that are chords.

5. Central Angle

An angle inside the circle with a vertex on the circle an two sides that are chords.

6. Inscribed Angle

Multiple Choice

An angle in a circle with vertex on the center of the circle

• Central angle

• Angle

• Inscribed angle

• Circle

Multiple Choice

An angle in a circle with vertex on the circle itself.

• Angle

• Central angle

• Inscribed angle

• Chord

Multiple Choice

Which number best represents an inscribed angle?

• 1

• 2

• 8

• 9

Multiple Choice

Which number best represents a central angle?

• 1

• 2

• 8

• 9

Multiple Choice

Which point is the point of tangency?

• A

• B

• C

• D

• E

A portion of the edge of the circle defined by two endpoints.

7. Arc

An arc with a measure less than 180⁰. Named using two points.

8. Minor Arc

An arc with a measure greater than 180⁰. Named using three points.

9. Major Arc

An arc with an 180⁰ measure, exactly. Named using two points.

​​10. Semicircle

Formula for finding the length of an arc as a portion of the circumference.

​​11. Arc Length Formula

​C is the circumference

x is the degree of the arc

l is the length of the arc.

Multiple Choice

Is arc FC a minor arc, major arc, or semicircle?

• minor arc

• major arc

• semicircle

Multiple Choice

Is arc EFD a minor arc, major arc, or semicircle?

• minor arc

• major arc

• semicircle

Multiple Choice

Is arc BC a minor arc, major arc, or semicircle?

• minor arc

• major arc

• semicircle

Multiple Choice

Is arc BD a minor arc, major arc, or semicircle?

• minor arc

• major arc

• semicircle

Match

Complete the formulas by matching.

• $$2\pi r$$

• $$\pi r^2$$

• $$\pi d$$

• $$\frac{x\cdot C}{360}$$

• $$\frac{Bh}{2}$$

=Circumference using radius

=Area of a circle

=Circumference using diameter

=Arc length

=Area of a triangle

• =Circumference using radius

• =Area of a circle

• =Circumference using diameter

• =Arc length

• =Area of a triangle