Are you ready? We heard you were going to make a few note cards - and then there might

be a short quiz. Have fun!!

White note card

circle

The set of all points in a plane that are equidistant from a given point

center

radius

diameterchordsNamed by its center: ОD D

Colored Note card

Circle formulas

Circumference: 2rArea: r²

Arc - part of a circle

Arc measure: a) degrees: equal to the measure of the

central angleb) length: central angle arc length

360° circumference =

Central angle

Major arc

Minor arc

This circle stuff is AWESOME!!

Hey, how about a quiz? That would

be fun!

You’re right! Everyone take out a piece of paper!

QUIZ

1.Draw circle E. Draw and label a radius, diameter, and a chord that is not a diameter.

2.Find the exact circumference and area of circle Q.

3.Name a minor arc in the circle.

4.Name a major arc in the circle.

5.Find the arc length of BC.

A B

C

Q95°

14 cm

Guess what!?! There is even more stuff to learn

about circles!

Colored note card

Angles in circles

Central angle • vertex is center of circle• sides are radii• measure is equal to arc

85°

85°

Inscribed angle• vertex is on circle• sides are chords• measure is half the arc

43°

86°

Try these! Find x.

x°

110°

56°

x°

36°

x°

x°

160°

Colored note card

Diameters and chords

congruent chords are equidistant from center

congruent chords = congruent arcs

diameter to chord – diameter bisects chord and arc

How about these? Math is good stuff!

8

6

Find the radius.3

x

12

y

Find x and y.

One more problem! Find the arc length of the minor

arc.

43°

4 cmcentral angle arc length 360° circumference

=

86360

X2 • • 4=

Think about the measure

of the arc. It’s not 43°!

86°

86°

Circumference: 2r

or 3.14?

Nice job!

X 1.91 6

More problems to do, there are, young Padawan.

Some with

factoring?

Factoring in two.

Fun in all of them.

More to learn, there is, young Padawan.

Tangents and secants to study, you must.

Secants and

tangents?

Secants and

tangents.