1. draw 4 concentric circles 2. draw a circle with r = 4 and center a. 3. what is the diameter of...
TRANSCRIPT
1. Draw 4 concentric circles
2. Draw a circle with r = 4 and center A.
3. What is the diameter of the circle?
4. Explain the difference between a secant & a chord5. What do you know about a tangent line and the radius drawn to the point of tangency?
Session 29
Math II
UNIT QUESTION: What special properties are found with the parts of a circle?Standard: MM2G1, MM2G2
Today’s Question:How do we use angle measures to find measures of arcs?Standard: MM2G3.a,d
P
A
BC
Central Angle : An Angle whose vertex is at the center of the
circleMinor ArcMajor Arc
Less than 180°
More than 180°
ABACB
To name: use 2 letters
To name: use 3 letters
APB is a Central Angle
P
E
F
D
Semicircle: An Arc that equals 180°
EDF
To name: use 3 letters
THINGS TO KNOW AND REMEMBER ALWAYS
A circle has 360 degrees
A semicircle has 180 degrees
Vertical Angles are Equal
measure of an arc = measure of central angle
A
B
C
Q 96
m AB
m ACB
m AE
E
=
=
=
96°
264°
84°
Arc Addition PostulateA
B
C
m ABC =
m AB + m BC
Tell me the measure of the following arcs.
80100
40
140A
B
C
D
R
m DAB =
m BCA =
240
260
Congruent Arcs have the same measure and MUST come from the same circle or of congruent circles.
4545
A
BC
D
110
Classwork
•Workbook Page 204 #12-24
• Homework:
TEXT Book: page 193 #9-23
page 201 #1-10