1. A. Daily Routine:
1. Prayer
Good morning class. Before we start may we
all stand up and pray. (The teacher will pray)
2. Cleaning
Ok class, before you sit down; please pick up
the pieces of paper and trash.
3. Greeting
Good morning once again class.
So how are you doing today?
Well, good then. 
A. Daily Routine
1. Prayer
The students will stand up and pray.
2. Cleaning
The students will pick up the pieces of paper
and trash then the class will sit down.
3. Greeting
Good morning teacher!
(different responses)
I. Objectives
Within the period, students are expected to:
A. Discover the area formula for triangles.
B. Answer problems involving area of triangles.
C. Apply what they have learned in real life.
II. Subject Matter
Topic: Area of Triangles
References: http://www.mathgoodies.com/lessons/Vol1/area_triangle.html
http://illuminations.nctm.org/Lesson.aspx?id=1874
Materials: ruler, scissor, pencil

2. 4. Checking ofattendance
Are there any absents today?
Very good!
B. Priming
1. Recall
Before we begin to our lesson, let us have a
recap on our past lesson. So who can still recall
our past lesson yesterday?
So let’s hear student A.
Very good!. 
So last time we studied about the area of
parallelogram. Who still remember the
formula in solving for the area of
parallelogram?
Let’s call for student B.
Very good! 
Thank you student B.
2. Motivation
Okay class, who wants prizes?
So many of you want prizes. Well I have a
puzzle here. I want someone to assemble the
pieces together and create a right triangle from
it. Whoever assembles the puzzle will get a
prize. Any volunteer?
4. Checking ofattendance
None
B. Priming
1. Recall
Students will raise their hands.
The past lesson was about the area of
parallelogram.
Students will raise their hands.
Area of a parallelogram is equal to base times
height.
2. Motivation
The students will raise their hands.
The students will raise their hands.

3. Okay, student C, give it a try.
Very good! Let’s give him a round of
applause.
Well, I have another question. Is it possible to
rearrange the pieces and come up with a
triangle with the same base and same height
yet have a missing area without excluding any
pieces?
Who can give it a try?
How about you student D?
(If the student solve the puzzle, the teacher
will say)
Very good! That was a hard one. Let us give
him a round of applause.
(if no one solve the puzzle, the teacher will
say)
Thanks for trying. Anyone else?
So if nobody wants to try it, let me show you
how it is done. (the teacher will show the class
how to solve the puzzle)
C. Activity
So from our activity, who could guess our
topic for today?
Let’s call student E.
That’s correct! Thank you student E.
So our topic today is about area of triangles. I
know every one of you knows what a triangle
is.
Student C will assemble the puzzle.
The students will clap.
Different responses
Some students will raise their hands.
Student D will try to assemble the puzzle.
The students will clap together.
No one raise his hand.
C. Activity
Students will raise their hands.
I think our lesson for today is about area of a
triangle.

4. I want you to group yourselves into 3 groups.
Now that you have grouped yourselves, I will
give each group activity sheets. All members
should participate, ok? And don’t make loud
noises.
Ok, very well then. 
(the teacher will distribute the activity sheets
to each group.)
Did you bring scissors and ruler?
Very good. You will need that in our activity.
So the instructions are written on the activity
sheets. After that, record the data and answer
the following questions. Group 1 will answer
question no. 1; group 2, question 2; group 3,
question 3.
D. Analysis
1. What are the area of the rectangles A, B
and C? How about the triangles they
formed?
2. What is the sum of the areas of the two
triangles formed by rectangle A? Is it
equal to the area of the same rectangle?
How about B and C?
3. What is the area of the largest triangle
formed by rectangle D? What can you say
about its area compare to its original
shape?
The students will grouped themselves into 3
groups.
Yes teacher.
The students will scan the activity sheet.
Yes teacher.
.
The students will do the activity.
D. Analysis

5. OK class. Time’s up!
So may I call each group’s representative to
present their findings?
Very well said! Thank you every one for your
cooperation. Let us give ourselves a round of
applause.
The students will stop what they are doing
and will sit properly
Group’s representative will come in front and
present their findings.
Group 1:
 Rectangle A has an area of 16 units2
and its triangles both have an area of 8
units2.
 Rectangle B has an area of 24 units2 and
its triangles both have an area of 12
units2
 Rectangle C has an area of 12 units2
and its triangles both have an area of 6
units2
Group 2:
 The sum of the triangles of rectangle A
is 16 units2 and it has the same area
with its original shape, the same goes
to other.
Group 3:
 The estimated area of the largest
triangle is 17 units2 and its original
shape’s area is 35 units2. Its largest
triangle is about the half of its original
area.
The students will clap their hands.

6. E. Abstraction
You all did great in our activity. 
So now let us go to the discussion.
What can you say about the area of the area of
the rectangles and the triangles they formed?
Very good! 
Now let me ask you, if the area of rectangle or
any parallelogram is equal to base times
height, what is the formula for the area of a
triangle?
Very good.! 
You have discovered by yourselves the
formula for finding the area of a triangle. You
are now mathematicians. 
The formula for finding the area of a triangle is
A= ½bh since the area of a triangle is one half
of the area of parallelogram.
So now let us have examples.
Find the area of the given triangle:
May we have a volunteer?
Ok student F, try to solve it. 
E. Abstraction
The area of the triangle is equal to one half of
their original shape.
The area of triangle is equal to one half of the
area of parallelogram or ½bh.
Student F will raise his hand
Student will answer the example.
The area of the triangle is equal to 27 cm2

7. That is correct!. 
Very good student F.
Reminder guys, never ever forget the units,
ok?
Another example
Try to solve this:
Anyone from the class?
Student G, can you show us your answer in
the board?
Very good Student G. 
You may now take your seat.
Generalization
Are there any questions?
So let us have a recap.
What is the formula in finding the area of a
triangle?
Very good! 
How did we get the formula for the area of the
triangle?
Very good. 
You all did understand the lesson.
Yes teacher!
Students will raise their hands.
Student G will show his answer in the board.
The answer is 30 in2.
The student will take his seat.
Generalization
None teacher!
The area of a triangle is equal to base times
height.
We got our formula since the area of triangle is
one half of the area of rectangle.

8. F. Application
Okay class, since there are no more questions
and you all understood the lesson; please
answer the problems in the questionnaires that
will be handed to you.
(the teacher will distribute the questionnaire)
Solve for the following:
1. A triangular garden has a baseof 12m and
a height of 7m. Find thearea of the garden.
2. A pyramid has a triangular base.It covers
4,350 ft2 of theland and has equal sides of
87 ft. What is the height of the base of the
pyramid?
3. If a triangular field has an area of 150m2
and a height of 20m. What is its base?
Okay guys, times up. Please pass your papers
to the front. And please copy your
assignments.
IV. Assignment
Answer the following.
1. A trianglehas an area of 25m2. It has a base
of (2x + 1)m and a height of (3x + 4)m. Find the
measure of thebase and the height.
2. Find thearea of an equilateral triangle
whose sides are10m in length.
3. The perimeter of an isosceles triangleis 16
meter and has an area of 12m2. Its height is
4m. Find the measureof its sides.
So goodbye class.
See you tomorrow. 
F. Application
The class will answer the problems.
The students will stop writing and will pass
their paper to the front.
Good bye teacher!. 