6th Grade Math Textbook, Fundamentals

Use the circle for exercises 1–6.

1.Name two central angles and two inscribed angles.

2.Name a semicircle, a minor arc, and a major arc.

3.Name a pair of supplementary central angles.

4.What is the measure of?

5.What is the measure of JLM?

6.Given that JKLMis a rectangle, name two pairs of

parallel chords.

7.Discuss and Write In what ways is a circle like a polygon?

How does it differ?

JKL

Lesson 9-12 for exercise sets. &KDSWHU 

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Circles are if they lie

in the same plane and have the

same center.

concentric

Secant CDcontains chord CD.

A

B

C

M

D

C

B

A

O

A circle is in a polygon if each side of

the polygon is tangentto the circle. Circle Pis

inscribed within triangle QRS.

A polygon is by a circle if all the

vertices of the polygon are points on the circle.

Triangle QRSis circumscribed by circle M.

Q

M

R

P

S

circumscribed

inscribed

J

M

N

L

K

56

An is an angle whose vertex is on the

circle and whose sides intersect the circle at other points.

• Its measure is half of the central angle that forms
  the same arc. BACis an inscribed angle.


• mBAC()mBMC

Tangents and secants are lines that intersect a circle.

A to a circle is a line in the plane of the circle.

The tangent intersects the circle at exactly one point.

ABis tangent to circle Oat point A.

A is a line that intersects a circle at two points.

CDintersects circle Oat points Cand D.

You can identify some circle relations.

1

2

secant

tangent

inscribed angle