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Republic of the Philippines
DEPARTMENT OF EDUCATION
Region XI
DIVISION OF DAVAO CITY
Davao City
DAVAO CITY NATIONAL HIGH SCHOOL
F. Torres St., Davao City
Telefax No. (082) 227 9102
LESSON PLAN
MATHEMATICS 8
Date: March 8 , 2022
I. COMPETENCY:
โข Illustrates triangle congruence. ( M8GE - IIId - 1 )
II. OBJECTIVES: At the end of the lesson, the students are expected to:
A. Define triangle congruence
B. Draw and label the corresponding parts of two congruent triangles
C. Relate triangle congruence in real-life.
III. SUBJECT MATTER:
A. Topic โ Illustrating Triangle Congruence
B. References: Mathematics 8 Quarter 3: Module 2
C. Materials: Laptop, Self-Learning Module, PowerPoint, Google Meet, WIFI
IV. PRELIMINARIES
- Prayer
- Checking of Attendance
- Classroom Rules
V. LESSON PROPER
- Activity/Motivation
Activity 1: Identify V-A-S (Vertices-Angles-Sides)
Directions: Identify the vertices, angles, and sides of each triangle. Then,
answer the questions below using complete sentences.
Vertices Angles Sides
Questions:
1. How did you identify the vertices, angles, and sides of each triangle?
2. How would you define angle?
3. What about the definition of a vertex?
4. In geometry, what is meant by side?
Actvity 2: Four Pic โ Two Words
Directions: Consider the figures below and answer the questions that follow.
- Analysis
- Teacher will ask the students. 1. What geometric figures were highlighted in the illustrations? 2. What have you observed with the size and shape of the geometric
figures? Explain your answer.
- Abstraction
Congruent
When two items have the exact same size and shape
Correspondence
Pairing the parts of one group to the parts of another group.
Correspondence uses the notation โโโ.
Congruent Triangles
Two triangles are congruent if and only if the corresponding sides and the
corresponding angles are congruent.
Vertices Angles Sides
The congruent sides go in order as well.
๐ฝ๐พ
ฬ
ฬ
ฬ
โ
๐๐
ฬ
ฬ
ฬ
ฬ
(first & second letters)
๐พ๐ฟ
ฬ
ฬ
ฬ
ฬ
โ
๐๐
ฬ
ฬ
ฬ
ฬ
(second & third letters)
๐ฝ๐ฟ
ฬ
โ
๐๐
ฬ
ฬ
ฬ
ฬ
(first & third letters)
This means that if two triangles are congruent, then their corresponding
parts are also congruent. (Corresponding Parts of Congruent Triangles are
Congruent). This is actually a restatement of the definition of congruent
triangles. Since this will often be used as reason in proofs, it is convenient to
use the abbreviation, CPCTC.
Example 1:
Given that โDBC โ
โYWX, name all the corresponding parts.
Solution:
The correspondence of the vertices can be used to name the congruent
sides and angles of the two triangles.
Corresponding Sides Corresponding Angles
๐ท๐ต
ฬ
ฬ
ฬ
ฬ
โ
๐๐
ฬ
ฬ
ฬ
ฬ
ฬ
๐ต๐ถ
ฬ
ฬ
ฬ
ฬ
โ
๐๐
ฬ
ฬ
ฬ
ฬ
ฬ
๐ท๐ถ
ฬ
ฬ
ฬ
ฬ
โ
๐๐
ฬ
ฬ
ฬ
ฬ
- Application
a. The teacher will let the student answer each question in the diagram below.
- Generalization
Two triangles are congruent if their vertices can be paired such that
corresponding sides are congruent and corresponding angles are congruent.
Designs and patterns having the same size and the same shape are seen in
almost all places. You can see them in bridges, buildings, towers, in furniture
even in handicrafts, and fabrics.
Congruence of triangles has many applications in the real world. Architects
and engineers use triangles when they build structures because they are
considered to be the most stable of all geometric figures. Triangles are
oftentimes used as frameworks, supports for many constructions works. They
need to be congruent.
VI. EVALUATION/ASSIGNMENT
Students will proceed to www.quizizz.com for the short quiz.
- In the figure โ๐๐๐บ โ
โ๐๐๐
, what is the side
corresponding to ๐
๐
A. ๐บ๐
B. ๐๐
C. ๐
๐
D. ๐๐บ
