Republic of the Philippines
PHINMA UNION COLLEGE OF LAGUNA
Santa Cruz, Laguna
Detailed Lesson Plan In Mathematics 5
I. OBJECTIVES
At the end of the lesson, the learners should be able to:
a. visualize area of a circle
b. derive a formula of a circle
c. find the area of a given circle, and
c. solve routine and non-routine problems involving the area of the circle.
I. Subject Matter
Topic: Finding the area of a circle
References: Mathematics curriculum guide p. 168
Materials: pictures, activity cards, activity sheets, manila paper, Powerpoint
presentation
Values Integration: Perseverance
II. Procedure
Teacher’s Activity
Learner’s Activity
A. Preliminary activities
1. Prayer
Let us stand for a short prayer.
2. Greetings
Good morning, children.
3. Energizer
Let us sing the song “Oh It’s Math Time”.
4. Checking of Attendance
Are there any absent from the class?
5. Recalling of the Classroom Rules
Before we begin our lesson, let us recall
the what to do during classes.
Classroom Rules: The 5 P’s
1. Be positive
2. Be productive
3. Be respectful
4. Be participative
Good morning, ma’am.
Oh, it’s Math time
after all.
Oh, it’s Math time
after all
Oh it’s Math time
after all
Oh it’s Math time
after all
None, ma’am.
B. Development activities
Review of the Past Lesson
Let us have a short recap about our topic last meeting.
So, our topic yesterday is about Circle and Its parts.
Now, I will group you in two groups. I have here a
colored paper and a pencil. I want you to form a big
Circular drawing.
(The student will start their
activity)
Now ,Lets us see if your answer are correct.
The Circle has 4 parts, and these are the
1. Circumference - arc length of a circle.
2. Center - is a midpoint of the diameter of the circle.
3. Diameter - a line segment that passes through
the center and its endpoints are on the circumference
of a circle
4. Radius - is the half of a diameter.
C. Motivation
(Post a picture of a farm.)
What do you see in the picture?
That is a farm.
Correct! What worker utilizes a farm?
A farmer.
Give some examples of some plants that a farmer
plants in a farm.
(The pupils will answer.)
A farmer plants a lot of rice, and vegetables. They
stay under the hot sun just to plant and give food
to all people.
They work hard just to provide food for the people
especially their families.
Values Integration:
They are persevering. They have perseverance. A person
is persevering when he works hard even when faced with
challenges.
We should be persevering just like our farmers.
D. Modeling
Let us read the problem about this picture.
Mang Tonying has a circular plot of land. He plans
to plant tomatoes and eggplants. From the center, it measures
3 km to any border of the plot. What is the area of the
land?
Who is the farmer?
The farmer is Mang Tonying.
What is he planning to plant in his farm?
Correct! What is the distance from the center
of the plot to the border?
What is asked in the problem?
He plans to plant
tomatoes and eggplants.
It measures 3 km.
What is the area of the land?
Exactly. Let us discuss how to find the area of
a circle.
In finding the area of the circle, we need the radius
of the circle.
What is the radius in the problem?
The radius is 3 km.
In finding the area of a circle, we have to use this
formula:
𝐴 = 𝜋𝑟2
“A” stands for the area of the circle.
π is the pi. It’s value is 3.14. “R” stands for the radius of the
circle. The exponent “2”means that you have to multiply
the radius to itself.
Let us solve the problem.
A = 3.14 * (3km)2
A = 3.14 *
(3km*3km)
A = 3.14 (9km)2
A = 28.26 km2
What is the area of the circle?
The area of the circle is
28.26 km2
Correct! Always remember that the unit of
measurement is also squared in finding the area.
Let us have another problem.
Tita Lucing is making a circular biko. From its center,
it measures 15 centimeters to any border of the
circle.
What is the radius of the circle?
The radius is 15 cm.
Correct. Let us solve the problem.
A = 3.14 * (15cm)2
A = 3.14 *
(15cm*15cm)
A = 3.14 (225cm)2
A = 706. 5cm2
What is the area of the biko?
The area is 706. 5cm2.
Our next problem is a non-routine problem.
Princess draws a circle inside a square piece of paper
Whose are is 81cm2. . She makes sure that the circle
touches each side of the square. What is the area of
a circle. (illustrate the problem)
Now, who can draw a circle that touches each
Side of the square?
(The pupils will raise their
hand)
Yes, ________?
Very good!
Now, what is asked in the problem?
The are of a circle.
What is the formula in finding the
area of a circle?
A= π r2
So, we need the radius in order for us to find
the area of a circle. But how we can do that
when the given in the problem is the area of
a square which is 81cm2.?
It is said in the problem that the circle touches
each side of the square. As you can see in the
Illustration. This means that the side of the
square is equal to the diameter of a circle. As
we all know that the diameter is 2 times of
radius or radius is one-half of diameter.
Now , Let us solve the given problem.
Area of a Square
A = 81cm2
S = √𝐴
When we say square root, we are
going to think of a number that if
we multiply it by itself the result
will be the number that is inside
the square root sign.
(I will give example on how to
square root a number)
S = √81 𝑐𝑚2
S = 9 𝑐𝑚
Therefore the diameter of the
circle is 9cm.
(solve the area of the circle)
Therefore the area of the circle is
63.59 cm.
E. Guided Practice
1. Group Activity
Let’s have a group activity. I will group you
into three. Choose your leader.
Before we continue, let us recall the
guidelines in doing a group activity. Who can give
me the first reminder?
What are the other reminders?
Great! I will give the activity cards.
Read the directions carefully and write your solution
and answers in the manila paper provided. You have
5 minutes to do this activity.
(The pupils will choose
their leaders.)
Work with your group mates.
Read the directions.
Cooperate with your
group mates.
(The pupils will do the
activity.)
Group 1:
Lola Marissa made a big bibingka for the family. Its
radius is 20 centimeters. Find the area.
1,256 cm2
Group 2:
The playground’s radius measures 500 meters. What
is the area of the playground?
785,000 m2
Group 3:
Lolo Maximo made a circular fence for his chickens.
From the center of the land, it measures 1.5 km to the
border. What is the area?
7.065 km2
2. High Five
Find a partner. I will give you an activity sheet.
Read the directions and show your solutions on
1. Find the area of the circle with a radius of 3 cm.
28.26 cm2
2. Find the area of the circle with a radius of 20 cm.
1,256 cm2
F. Independent Practice
I will give you an activity sheet. Please read
the directions carefully. Write your solutions and
answers on the spaces provided.
1. Find the area of the circle with a radius of 14 cm.
615.44 cm2
2. Find the area of the circle with a radius of 20 dm.
1,256 dm2
III. EVALUATION
Direction: Solve for the area of the circles.
1. A race-track is in the form of a circular ring. The radius is 63 meters. Find the area of the racetrack.
2. A circular mirror has a radius of 21 cm. What is the area?
3. A circular clock has a radius of 35 cm. What is the area?
4. The radius of a circle is 10 meters. Find the area.
5. The radius of a race-track is 1.5 kilometers. What is the area?
Answers:
1. 12,462.66 m2
2. 1,384.74 cm2
3. 3,846.5 cm2
4. 314 m2
5. 7.065 km2
IV.
Assignment
Find the area of a circle whose radius is 567 meters.
Prepared by:
CARMELLA JOI O. AMBROSIO
Student Teacher
NAME: