DETAILED LESSON PLAN IN MATHEMATICSBy: Genaro Nocete de Mesa, Jr.

I. OBJECTIVES

During and after the lesson, the students are expected to:

1. measure the sides of a triangle using a ruler.2. classify triangles according to sides.3. cite significant applications of triangles in real life.

II. SUBJECT MATTER

A. Topic: Classification of Triangles According to sidesB. References: Geometry by: Julieta G. Bernabe, pages 10-11

http://wiki.answers.com/Q/Classification_of_triangle_according_to_sidesC. Materials: visual aids, ruler, activity sheets, pens, cut-out trianglesD. Skills: measuring, classifying, listening, critical thinkingE. Values to be integrated: teamwork, cooperation, participationF. Concepts:

The classifications of triangles according to sides are:1. Equilateral Triangle – A triangle in which all sides are of equal length.2. Isosceles Triangle – A triangle in which two sides are of equal length.3. Scalene Triangle – A triangle in which all sides are of different length.

G. Teaching Strategy: 4 A’s of learning (Activity, Analysis, Abstraction, Application)

III. LEARNING ACTIVITIES

TIME FRAME

TEACHING HINTS TEACHER’S ACTIVITY STUDENT’S ACTIVITY INSTRUCTIONAL MATERIALS

7 minutes A. Preliminary Activities1. Greetings2. Prayer

3. Classroom management

4. Checking of attendance

5. Checking of assignment

6. Recall

Good morning class!Everybody stand, let us pray. Karen, will you please lead the prayer?

Before you sit down, kindly arrange your chairs properly and pick up the pieces of dirt.

Class secretary, who are absent today?

Please submit your assignment.

Before we start our lesson, let us first recall your knowledge about the definition of triangle.

What is a triangle?

In the given figure,

Very good!

Good morning Sir!

(Karen will lead the prayer)

(The students will follow)

None Sir!

(The students will pass their assignment)

A triangle is a polygon with three sides.

The three sides are AB, BC and CA.

visual aid

B

A C

What are the three sides?

7 minutes

1 minute

1 minute

15 minutes

B. Motivation

C. Presentation of the Lesson

D. Presentation of the Objectives

E. Lesson Proper

1. Activity a. Pre-activity

b. Activity Proper

Before we proceed to our lesson, let us have first group activity. I will divide the class into six groups. Each group will make a collage of man using the cut-out triangles.

Are you done class?

Kindly post your outputs on the board.

Did you have fun doing the activity?

What can you say about the different cut-out triangles in terms of its sides?

What else?

Bright observations!

So, your answers have something to do with our lesson for today.

In connection with the activity that you’ve done, today, we are going to discuss about classification of triangles according to sides.

For today’s lesson, we have the following objectives.(Objectives will be post on the board.)Will you read them one by one?

Thank you!

To attain those objectives, let us have again group activity. At this point, since I already group you a while ago, each group will choose a leader/representative to present their output.

Here is the rubrics for grading your output: Cooperation – 5 points Accuracy – 3 points Presentation – 2 points TOTAL – 10 POINTS

Each group will be given 3 triangles to be measured.

(The students are performing the activity.)

Yes Sir!

(The students will follow)

Yes Sir!

Some triangles have two equal sides.

Some triangles have 3 equal sides, and some doesn’t have equal sides.

(The students will read the objectives.)

cut-out triangles

visual aid

5 minutes

c. Post-activity

2. Analysis

Directions: Measure the sides of the triangle. Record the data in the graphic organizer. Observe the length of the sides of the triangle.

Be sure that all members of the group will cooperate.

Graphic Organizer:

Triangle mof

AB

mof BC

mof

AC1.

2.

3.

Group leaders, are you ready?

Okay, let’s start with Group 1, followed by 2, 3, 4, 5 and 6.

Let us now discuss your outputs.

For group 1 and 2, what can you say about the measurement of the length of sides of the triangles?

Bright answer! So, the triangles measured by group 1 and 2 are classified as Isosceles triangle.

For group 3 and 4, what did you observe about the measurement of the sides of the triangle?

What else?

Correct! So, the triangles measured by group 3 and 4 are classified as Scalene triangle.

How about in group 5 and 6? What did you observe about the measurement of the sides of the triangle?

Very well said! So, the triangles

Triangle mof

AB

mof BC

mof

AC1.

2.

3.

Yes Sir!

(Group leaders presenting their outputs.)

Two sides have the same measure.

They have different measure.

No two sides have the same measures.

They have the same or equal measures.

visual aids, ruler, pens

visual aids

5 minutes

5 minutes

4 minutes

3. Abstraction

4. Application

5. Generalization

measured by group 5 and 6 are classified as Equilateral triangle.

Going back to the activity performed by group 1 and 2, why is it that the given triangles are said to be isosceles?

Very good! So, for the activity performed by group 3 and 4, why is it that the given triangles are said to be scalene?

Bright answer!

How about in the activity performed by group 5 and 6, Why is it that the given triangles are said to be equilateral?

Very well said!

To master more your skills in classifying triangles according to sides, let’s have once more activity. With the same group, classify the different triangles in the collage that you’ve done based on the first activity. Kindly write the classification in the respective pieces of triangles.

Are you done class?

Kindly submit the collage and I’ll be the one to check.

Since we are talking so much about triangles, the question is, where can you apply these concepts in real life?

What else?

Very good class!

Class, what did you learn in today’s lesson?

Again, what are the classifications of triangles according to sides?

Could you describe each

The given triangles are said to be isosceles since the two sides are of equal length.

The given triangles are said to be scalene since all sides are of different length.

The given triangles are said to be equilateral since all sides are of equal length.

Yes Sir!

(The students will follow.)

Triangles have many applications in real life; it can be applied in house constructions. Specifically, the roof of the house. Some of the roofs are in the form of triangle.

Also, triangles can be used in designing things.

We learned how to classify triangles according to sides.

The classifications of triangles according to sides are scalene, isosceles and equilateral.

classification of triangles according to sides?

So, is there any question?

Okay, let’s have a short quiz.(Activity sheets will be distributed)

(The students are describing the classifications of triangles according to sides.)

None Sir!

activity sheets

IV. EVALUATION ( 8 minutes)

Direction: Tell whether each triangle is isosceles, scalene or equilateral. Then explain your answer.(For example, write “because two sides are equal”)

1. I am a triangle whose sides measure 3 cm, 5 cm and 3 cm. What type of triangle am I?2. I am a triangle whose sides measure 5 cm, 5 cm and 5 cm. What type of triangle am I?3. I am a triangle whose sides measure 200 in, 300 in and 400 in.What type of triangle am I?4. I am a triangle whose sides measure 12 in, 15 in and 15 in. What type of triangle am I?5. I am a triangle whose two sides measure 14 cm and 17 cm. All of my sides are equal to 45 cm.

What type of triangle am I?

Expected Answers of the students:

1. Isosceles, because two sides are equal.2. Equilateral, because three sides are equal.3. Scalene, because none of its sides are equal.4. Isosceles, because two sides are equal.5. Isosceles, because two sides are equal.

V. ASSIGNMENT (2 minutes)

A. Answer the following:

1. If the sum of the sides of an equilateral triangle is 45 cm. What does each side measure?

2. If one sides of an Isosceles triangle measures 4 meters and another side measures 6 meters, What could the remaining side measure? (Give all possible answers.)

B. Research and study about classification of triangles according to angles.

Reference: Any Geometry books