Math10 q2 mod2of8_chords,arcs,central angles and incribe angles of circles_v2 (1)
1. Mathematics
Quarter 2 – Module 2:
Relationship Among Chords, Arcs,
Central Angles, and Inscribed Angles of
Circles
(M10GE-lic-1)
1
10
2. Development Team of the Module
Writer: Eva Jones D. Siangco, MScieEd-Math
Editors: (Language/Social Content): Rachelle T. Amando, PhD/George S. Hofer
Reviewers: Nora B. Mendoza /Maureen Socorro N. Muñasque
Illustrator: Geunicar A. Perez, MAELT
Layout Artist: Geunicar A. Perez, MAELT
Cover Art Designer:Ian Caesar E. Frondoza
Management Team: Allan G. Farnazo, CESO IV – Regional Director
Fiel Y. Almendra, CESO V – Assistant Regional Director
Concepcion F. Balawag, CESO V - Schools Division Superintendent
Edgar S. Sumapal - Assistant Schools Division Superintendent
Gilbert B. Barrera – Chief, CLMD
Arturo D. Tingson Jr. – REPS, LRMS
Peter Van C. Ang-ug – REPS, ADM
Jade T. Palomar - REPS, Mathematics
Pancho G. Balawag, Ed. D - CID Chief
Engr. Reynaldo SE Villan - EPS In Charge of LRMS
Vivencio O. Aniñon, Ed.D - Division ADM Coordinator
Engr. Reynaldo SE Villan – EPS, Math
2
Mathematics – Grade 10
Self-Learning Module (SLM)
Quarter 2 – Module 2: Relationship Among Chords, Arcs, Central Angles, And
Inscribed Angles of Circles
First Edition, 2020
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Office Address: Regional Center, Brgy. Carpenter Hill, City of Koronadal
Telefax: (083) 2288825/ (083) 2281893
E-mail Address: region12@deped.gov.ph
3. Introductory Message
This Self-Learning Module (SLM) is prepared so that you, our dear learners, can
continue your studies and learn while at home. Activities, questions, directions,
exercises, and discussions are carefully statedfor you to understand each lesson.
Each SLM is composed of different parts. Each part shall guide you step-by- step as
you discover andunderstand the lesson prepared for you.
Pre-test are provided to measure your prior knowledge on lessons in each SLM. This
will tell you if you need to proceed on completing this module, or if you need to ask
your facilitator or your teacher’s assistance for better understanding of the lesson. At
the end of each module, you need to answer the post-test to self-check your learning.
Answer keys are provided for each activity and test. We trust thatyou will be honest
in using these.
In addition to the material in the main text, Notes to the Teachers are also provided
to the facilitators and parents for strategies and reminders on how they can best help
you on your home-based learning.
Please use this module with care. Do not put unnecessary marks on any part of this
SLM. Use a separatesheet of paper in answering the exercises and tests. Read the
instructions carefully before performing each task.
If you have any questions in using this SLM or any difficulty in answering the tasks
in this module, donot hesitate to consult your teacher or facilitator.
Thank you.
4. 6
M
78°
E
S 95
L
B
M
O
What I Know
Find out how much you already know about topics on this module.
Choose the letter that you think best answers each of the following
questions.
1. What is an angle whose vertex is on a circle and whose sides contain
chords of the circle?
A. Central angle C. circumscribed angle
B. Inscribed angle D. intercepted angle
2. In circle S at the right, what is m∠VSI if m VI = 140?
A. 35 C. 140
B. 75 D. 230
3. What is the sum of the measures of the central angles of a circle with
no common interior points?
A. 120 C. 360
B. 240 D. 480
4. If an inscribed angle of a circle intercepts a semicircle, then the angle
is .
A. Acute C. obtuse
B. Right D. straight
5. In the circle below, what is the measure of ∠SAY if DSY is a
semicircle and m∠ SAD = 70?
A. 20 C. 110
B. 70 D. 150
6. Quadrilateral SMIL is incribed in oE. If m∠SMI = 78 and m∠MSL =
95, find m∠MIL.
A. 78 C. 95 I
B. 85 D. 102
7. In oM on the right, what is m∠BRO if m∠BMO = 60?
A. 120 C. 30
B. 60 D. 15
R
S
D
A
Y
5. 7
R
C
Great! You did a good job. You’re now ready for the next set of
activities.
E P
8. In U on the right, what is m∠PRE if m∠PUE = 56 ?
A. 28 C. 56 U
B. 34 D. 124
R
9. Catherine designed a pendant. It is a regular hexagon set in a circle.
Suppose the opposite vertices are connected by line segments and meet at
the center of the circle. What is the measure of each angle formed at the
center?
A. 22.5 B. 45 C. 60 D. 72
10. What is an angle whose vertex is any point on the circle and sides
contain chords of the circle?
A.central angle C. circumscribed angle
B. inscribed angle D. intercepted angle
11. The opposite angles of a quadrilateral inscribed in a circle are .
A. right C. complementary
B. obtuse D. supplementary
12. What is an arc with a measure equal to one-half the circumference of
a circle?
A. Major arc C. inscribed arc
B. Minor arc D. semicircle
13. In oT on the right ,PIO and PLO intercept PO.
If mPIO= 55, what is the m PO?
P
A. 110 C. 55
B. 95 D. 40
For items 14 & 15.
In oA, SE NE and SC NT.
14. If m SE = 80, then what is m T?
A. 100 C. 80
B. 90 D. 40
S
15. If m then what is m SC?
A. 60 C. 100
B. 70 D. 120
N
A T
E
O
T
I L
6. 8
Let’s remember the lesson in your previous level about circles. This
time we will focus on relationship between chords, arcs and central angles of
circles. Are you ready?
Lesson
2
CHORDS, ARCS ,CENTRAL
ANGLES, INSCRIBED ANGLES AND
INTERCEPTED ARCS
Congratulations! You are now ready to start with another module. Start
Lesson 3.1 of this module by evaluating your knowledge of the various
previously studied mathematical concepts and your skills in mathematical
operations. These knowledge and skills will help you understand circles.
Think about the crucial question as you go through this lesson: “How do the
relationships among chords, arcs, central angles, inscribed angles and
intercepted arcs of a circle facilitate finding solutions to real-life problems
and making decisions?” Carry out each operation to find the answer. If you
encounter some trouble in reacting to the exercises, seek guidance from your
instructor or peers or refer to the modules you learned earlier. You should
check with your teacher about your work. (M10GE-lic-1).
What’s In
Circle
In geometry, a circle is a closed curve formed by a set of points on a
plane that is the same distance from its center O. That distance is known as
the radius of the circle.
Radius
The radius of the circle is a line segment from the center of the circle to a
point on the circle. The plural of radius is radii.
7. 9
2
In the above diagram, O is the center of the circle and OB and OC are radii
of the circle. The radii of a circle are all of the same length. The radius is half
of the length of the diameter.
Diameter
OB = 1 AB
The diameter of a circle is a line segment that passes through the
center of the circle and has its endpoints on the circle. All the diameters of
the same circle have the same length.
Chord
A chord is a line segment with both endpoints on the circle. The
diameter is a special chord that passes through the center of the circle. The
diameter would be the longest chord in the circle.
Arc
An arc is a part of a circle.
In the diagram above, the part of the circle from B to C forms an arc
8. 10
Have you ever seen pulling a cart, or riding a bus with wheels that aren't
round? Do you think you can easily move heavy items from one location to
another, or fly far away as quickly as you can? Without circles, what
challenge do you think you will experience? Have you ever noticed the
importance of circles in travel, manufacturing, leisure, navigation, carpentry
and in your daily life?
What’s New
An arc can be measured in degrees.
In the circle above, arc BC is equal to the ∠BOC that is 45°.
INTRODUCTION
This module focuses on the relationship between chords, arcs, central and
inscribed angles of circles and how the concept is utilized in our daily life.
Study the situation below and answer the questions that follow.
Find out the answers to these questions and determine the vast
applications of circles through this module.
Let’s try with our first activity.
Activity 1. Know My Terms and Conditions
Use the figure below to identify and name the following terms related to oA.
Then, answer the questions that follow.
1. a radius 5. a minor arc J
2. a diameter 6. a major arc
3. a chord 7. two central angles L N
4. a semicircle 8. two inscribed angles
A
s E
9. 11
N
I G
U
Are you in a position to define and explain the terminology of the circles?
Can you identify and distinguish them? Now that you are aware of the
essential circle-related terminology, let us deepen your understanding of
finding angle measures in a circle. You need this mathematical ability to
identify the relationships as you go through this lesson between chords,
arcs, and central angles.
Questions:
a. How did you identify and name the radius, diameter, and chord?
b. How about the semicircle, minor arc, and major arc? inscribed
angle and central angle?
c. How do you describe a radius, diameter, and chord of a circle?
d. How about the semicircle, minor arc, and major arc? inscribed
angle and central angle?
Write your answers in the table below.
Terms Related to Circles Description
1. radius
2. diameter
3. chord
4. semicircle
5. minor arc
6. major arc
7. central angle
8. inscribed angle
e. How do you differentiate among the radius, diameter, and chord
of a circle?
f. How about the semicircle, minor arc, and major arc? inscribed
angle and central angle?
10. 12
What is It
How did you approach the events previous to this? Are you prepared to
learn about a circle 's relationships among chords, arcs, central, inscribed
angles and intercepted arcs?
I 'm sure you really are!!! You have been able to recall and explain the
terms relating to circles from the things you have performed. You were able
to find out how the circles in real-life situations are represented. But how do
the relationships among a circle's chords, arcs, central, inscribed angles and
intercepted arcs promote the discovery and decision making of solutions to
real-life problems? You will find these out in the next portion of the events.
Before performing these exercises, first read and understand some important
information about this lesson and the examples that were given.
Central Angle and Arcs
Recall that a central angle
of a circle is an angle formed by
two rays whose vertex is the
center of the circle. Each ray
intersects the circle at a point,
dividing it into arcs.
In the figure on the right, BAC is a central
angle. Its sides divide A into arcs. One arc is
the curve containing points B and C. The
other arc is the curve containing points B, D, and C.
Definition: Sum of Central Angles
The sum of the measures of
the central angles of a circle with
no common interior points is 360
degrees.
In the figure, m1+ m2 +m3 + m4 = 360 .
(Note: All measures of angles and arcs are in degrees.)
Arcs of a Circle
An arc is a part of a circle. The symbol for arc is .
A semicircle is an arc with a measure equal to one-half
the circumference of a circle.
It is named by using the two endpoints and
another point on the arc.
arc
C
B
central
angle
A
arc
D
11. 13
Example: The curve from point N to point Z is an arc.
It is part of O and is named as arc NZ or NZ.
Other arcs of O are CN, CZ, CZN, CNZ, and NCZ.
If mCNZ is one-half the circumference of O, then it
is a semicircle.
Z
A minor arc is an arc of the circle that
measures less than a semicircle. It is named N
Usually by using the two endpoints of the
arc.
Example: JN. NE and JE.
A major arc is an arc of a circle that
measures greater than a semicircle. It is
J
named by using the two endpoints and
another point on the arc.
Example: JEN. JNE and EJN.
Degree Measure of an Arc
1. The degree measure of a minor arc is the
measure of the central angle which
intercepts the arc.
Example: GEO is a central angle. It
intercepts E at points G and O.
The measure of GO is equal to the measure
of then mGO = 118.
2. The degree measure of a major arc is
equal to 360 minus the measure of the
minor arc with the same endpoints.
Example: If mGO = 118, then mOMG = 360-
mGO. That is, mOMG = 360 – 118 = 242.
Answer: mOMG = 242.
3.The degree measure of a semicircle is
180o.
C
O
N
A
E
O
G E
M
12. 14
K
Congruent Circles and Congruent Arcs
Congruent circles are circles with
congruent radii.
Example: MA is a radius of A.
TH is a radius of T.
If MA TH , then A T.
T
Congruent arcs are arcs of the same
circle or of congruent circles with equal M
measures.
Example: I, TM KS . K
W
If I E, then TM NW.
and KS NW.
Theorems on Central Angles, Arcs, and Chords
1. In a circle or in congruent circles, two
minor arcs are congruent if and only if
their corresponding central angles are
congruent.
In E below, SET NEO. Since the two
central angles are congruent, the minor
arcs they intercept are also congruent. S
Hence,
ST NO .
If E I and SET NEO BIG,
then ST NO BG .
2. In a circle or in congruent circles, two minor arcs are
congruent if and only if their corresponding chords are
congruent.
A
M
T
H
B
G
50°
I
T O
50° 50°
N
E
65°
I
N
65° S
65°
E
13. 15
M
U
A
In T on the right, BA CH . Since the two
B
chords are congruent, then BA CH .
T N and BA CH OE , then
BA CH OE .
E
3. In a circle, a diameter bisects a chord and an arc with the same
endpoints if and only if it is perpendicular to the chord.
In U on the right, ES is a diameter and GN is a chord.
G
If ES ┴ GN, then GI IN and GE EN. S
I
E
N
Inscribed Angles and Intercepted Arcs
An inscribed angle is an angle whose vertex is on a circle and whose
sides contain chords of the circle. The arc that lies in the interior of an
inscribed angle and has endpoints on the angle is called the intercepted arc
of the angle.
Examples:
G
C
Figure 1 Figure 2 Figure 3
In Figure 1, LAP is an inscribed angle and its intercepted arc is LP.
The center of the circle is in the interior of the angle.
In Figure 2, TOP is an inscribed angle and its intercepted arc is TP.
One side of the angle is the diameter of the circle.
T H
C
N
O
L
T
P
P
A O
14. 16
A
T
I L
O
T
N
S
O
In Figure 3, CGM is an inscribed angle and its intercepted arc is CM.
The center of the circle is in the exterior of the angle.
Theorems on Inscribed Angles
1. If an angle is inscribed in a circle, then the measure of the angle equals
one-half the measure of its intercepted arc (or the measure of the intercepted
arc is twice the measure of the inscribed angle).
Example: In the figure on the right, ACT is
an inscribed angle and AT is its intercepted arc.
C
If mAT = 120, then mACT = 60.
2. If two inscribed angles of a circle (or congruent circles) intercept
congruent arcs or the same arc, then the angles are congruent.
Example 1: In Figure 1 below, PIO and PLO intercept PO. Since
PIO and PLO intercept the same arc, the two angles, then, are congruent.
Figure 1 Figure 2
P
S E
I L M P
Example 2: In Figure 2 above, SIM and ELP intercept SM and EP,
respectively. If SM EP , then SIM ELP.
3. If an inscribed angle of a circle intercepts a semicircle,
then the angle is a right angle.
Example: In the figure, NTE intercepts NSE.
T
If NSE is a semicircle, then NTE is
a right angle.
E
15. 17
R
M
A
E
4. If a quadrilateral is inscribed in a circle, then its opposite angles are
supplementary.
Example: Quadrilateral DREA is inscribed in M.
mRDA + mREA = 180.
mADR + mDAE = 180.
D
Whew! That’s a nice job there. Let’s explore some more exercises for our
brain development.
What’s More
Your goal in this section is to apply the key concepts of chords, arcs,
central, inscribed angles and intercepted arcsarcs and inscribed angles of a
circle. Use the mathematical ideas and the examples presented in the
preceding section to answer the activities provided.
Activity 2. Find me!
In the figure, JI and ON are diameters of S . Use the figure and the
given
information to answer the following. J
1. Which central angles are congruent? Why? O
2. If mJSN = 113, find:
a. mISO S
b. mNSI
c. mJSO
N
I
3. Is OJ IN ? How about JN and OI ? Explain your answer.
4. Which minor arcs are congruent? Explain your answer.
5. If mJSO = 67, find:
a. mJO d. mIO
b. mJN e.mNJO
c. mNI f.mNIO
6.Which arcs are semicircles? Why?
16. 18
A
C
M 6 K
3
2 7
B
D
P
Wow! You made it. You are now acquainted with solving problems on
sequences. Let’s continue in the next activity.
Activity 3. Get My Length
In M below, BD = 3, KM = 6, and KP = 2√7. Use the figure and the
given information to find each measure.
1. AM 5. DS
2. KL 6. MP
3. MD 7. AK L
4. CD 8. KP
S
Activity 4. Inscribe, Intercept then Measure
In the figure below, CE and LA are diameters of N. Use the figure to
answer the following.
1. Name all inscribed angles in the figure.
2. Which inscribed angles intercept the following arcs?
L
a. CL c. LE C
b. AE d. AC
3. If mLE = 124, what is the measure of
each of the following angles?
a. 1 d. g.
b. e. h. A
c. f. i.
4. If m1=26, what is the measure of each of the following arcs?
a.CL b.AC c. AE d. LE
4 N
5 6
7
8
E
17. 19
Good job! Now you’re up for the final challenge of this module.
What I Have Learned
Here is another activity that let you apply what you have learned about
relationship among chords, arcs, central, inscribed angles and intercepted
arcs. Are you ready?
Fill in the blanks with the correct word/s or symbol/s that best fit/s the
statement.
1. The length from the center of the circle to any point on the circle is called
.
2. A angle is an angle equal to its intercepted arc.
3. If a chord passes through the center of a circle, then it is a of a
circle.
4. An angle is equal to one-half the measure of its intercepted arc.
5. A is equal to half of a circle.
6. If two chords of congruent circles are equal, then their arcs are also
equal.
7. The measure of the intercepted arc of a right angle is .
8. The sum of the measures of all the central angles of a circle is .
9. The measure of a arc of a circle is more than 180o but less than
360o.
10. A is a segment containing any two points on the circle.
18. 20
Amazing! You really did a good job!
What I Can Do
Let us test your awareness and skills further by trying out another activity.
Use the situation below to answer the questions that follow.
Claire works for a realtor. One of her jobs is to take photographs of
houses that are for sale. She took a photograph of a house two months ago
using a camera lens with 80° field of view like the one shown below. She has
returned to the house to update the photo, but she has forgotten her lens.
Now, she only has a telephoto lens with a 40° field of view.
Questions:
1. From what location(s) could Claire take a photograph of the house with
the telephoto lens, so that the entire house still fills the width of the picture?
Use an illustration to show your answer.
2. What mathematics concept would you apply to show the exact location of
the photographer?
3. If you were the photographer, what would you do to make sure that the
entire house is captured by the camera?
19. 21
Assessment
Let us determine how much you have learned in this module. Kindly
answer the following questions by choosing the letter of your answer.
For items 1 to 6
In F, AB , BC , CD , BD and AC are chords. Use the figure and the given
information to answer the following questions.
1. If mCBD = 54, what is the measure of CD?
A. 55 B. 78 C. 96 D.108
2. If mAB = 96, what is the measure of ACB ?
A. 34 B. 40 C. 48 D.54
If mABD = 5x + 3 and mDCA = 4x + 10 ,
3. Find the value of x D
A. 7 C. 9
B. 8 D. 10
A
4. What is the mDCA?
A. 34 C. 44
B. 38 D. 48
5. What is the mABD? B
A. 34 B. 38 C. 44 D. 48
6. What is the mAD?
A. 72 B. 74 C. 76 D.78
7. What is also called as the longest chord of the circle?
A. arc B. angle C. chord D. diameter
8. If A is a central angle and its measure equals 50o, then what is the
measure of its intercepted arc?
A. 100o B. 50o C. 40o D. 25o
9. If
and it is an inscribed angle, then what is the measure of its
intercepted arc?
A. 50o B. 100o C. 150o D. 200o
F
E
C
20. 22
F
75°
H
98°
For items 10 to 11
In the figure below, CE and LA are diameters of N. Use the figure to
L
answer the following.
10. If m=26, what is the measure of CL?
A. 38 C. 48
B. 45 D. 52
11. If m AE = 84, what is the m1?
A. 36 C. 54 A
B. 42 D. 60
For items 12 to 13
∆GOA is inscribed in L. If mOGA = 75 and m AG =160,
12. What is the m OA?
A. 150 C. 90
B. 100 D.80
13. What is mGAO
A. 30 C.15
B. 25 D.10
O
L A
75
G
160
For items 14 to 15
Quadrilateral FAIT is inscribed in H. If m AFT =75 and m FTI = 98,
14. What is m TIA?
A. 95 C. 105
A
B. 100 D. 110
15. What is m FAI?
A. 82 C. 86
T
B. 84 D. 88 I
Amazing! You've done well on this module!
C
4 N
5 6
7
8
E
21. 23
Soriano Family’s
Monthly Expenses
Congratulations! Job well done. I hope you learned a
lot in this module. You are now ready to answer the
next module on circles.
Additional Activities
Here's another practice that will help improve your knowledge and skills.
Budget Case
The monthly income of the Soriano family is Php36,000.00. They spend
Php9,000.00 for food, Php12,000.00 for education, Php4,500.00 for utilities,
and Php6,000.00 for other expenses. The remaining amount is for their
savings. This information is shown in the circle graph below.
a. Which item is allotted with the highest budget? How about the least?
Explain.
b. If you were to budget your family’s monthly income, which item would
you give the greater allocation? Why?
c. In the circle graph, what is the measure of the central angle
corresponding to each item?
d. How is the measure of the central angle corresponding to each item
determined?
22. What’s New
Activity 1. AN, AJ, AE 5. JL, JN, EN, EL
1. EJ
2. EL, EJ
6. LEN, LJE, ENL, JLN, LNE
7. JAN, NAE
3. JNE, JLE 8. LEJ, JEN
Questions:
Recall the definition of the terms related to circles.
Terms
related to
circle
Description
1. radius It is a segment drawn from the center of
the circle to any point on the circle.
2. diameter It is a segment whose endpoints are on the
circle and it passes through the center of the
circle. It is the longest chord.
3. chord It is a segment joining any two points on
the circle.
4. semicircle It is an arc measuring one-half of the
circumference of a circle.
5. minor arc It is an arc of a circle that measures less
than a semicircle.
6. major arc It is an arc of a circle that measures
greater than a semicircle.
7. central
angle
It is an angle whose vertex is at the center
of the circle and with two radii as its sides.
8. inscribed
angle
It is an angle whose vertex is on a circle
and whose sides contain chords of the
circle.
26. For inquiries or feedback, please write or call:
Department of Education – SOCCSKSARGEN
Learning Resource Management System (LRMS)
Regional Center, Brgy. Carpenter Hill, City of Koronadal
Telefax No.: (083) 2288825/ (083) 2281893
Email Address: region12@deped.gov.ph
EDITOR’S NOTE
This Self-learning Module (SLM) was developed by DepEd SOCCSKSARGEN
with the primary objective of preparing for and addressing the new normal.
Contents of this module were based on DepEd’s Most Essential Learning
Competencies (MELC). This is a supplementary material to be used by all
learners of Region XII in all public schools beginning SY 2020-2021. The
process of LR development was observed in the production of this module.
This is version 1.0. We highly encourage feedback, comments, and
recommendations.
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