**Priming**

1. Why/How did you choose your partner?

2. Describe the two figures you have?

3. What can you say about the size and shape of the two figures?

4. We say that congruent figures have the same shape and the same size. Verify your answer.

**CONGRUENT TRIANGLES**

1. What are the properties of a triangle?

2. Why are triangles important in the construction of bridges?

3. What other structures can you see around you - have triangles?

4. What is you idea of congruent triangles?

ACTIVITY 1

picture analysis

1. How will you relate the picture to your ambition?

2. If you were an architect or an engineer, what would be your dream project?

3. What can you say about the long bridge? How about the tall building? How stable is a structure that uses triangles? What is the importance of bridges to economic progress?

4. Why are there triangles in the structures? Are the triangles congruent?

5. Why are bridges and buildings stable?

ACTIVITY 2

FIND YOUR PARTNER

Match your shape with another's shape....

analysis

abstraction

2. Is it important to understand the

properties of a triangle?

Why or why not?

3.What are the

similarities and

differences

in your answers?

4. What are the problems

that you have

encountered while

performing the activities?

5. What insights

have you

gained from

the activities?

1. Two triangles are congruent

if their vertices

can be paired such

that corresponding sides

are congruent

and corresponding angles are congruent.

2. Triangles are considered

as the most stable

of all geometric figures.

3. Buildings,

bridges, quilts, etc.

are some examples of triangles in real life.

4. Triangles are used to give stability

and to reinforce strength in materials used.

Definition of Congruent Triangles

Application

GRASPS TASK

Many bridges were destroyed in the Visayas Region when storm “Yolanda” came to the Philippines . If you were an engineer how would you design your bridge and convince the people in the community that the design is stable and strong? Show a miniature of your bridge using toothpicks or craft sticks and glue. Your output will be evaluated according to its stability and mathematical reasoning.

by: CAROLINE J.BOBILES

GNHS

For each group pick up a pair of congruent triangles

1. In which pairing or match the two triangles coincide?

2. How many pairs of corresponding parts are congruent?

3. What are congruent triangles

4. Where do you see congruent triangles

1. What can you say about the activities?

5. Congruence of triangles

has many applications

in real world

CRITERIA Outstanding

4 Satisfactory

3 Developing

2 Beginning

1 Rating

Stability

4- The design is stable, comprehensive, and displays the aesthetic aspects of

the principles of triangle congruence .

3- The design is stable, presentable, and make use of congruent triangles.

2- The design makes use of triangles but not stable.

1- The design does not use triangles and is not stable.

Mathematical reasoning

4- The explanation is clear, exhaustive or thorough and coherent. It includes interesting facts and principles.

3- The explanation is clear and coherent. It covers the important concepts.

2- The explanation is understandable but not logical.

1- The explanation is incomplete and inconsistent.

OVERALL

RATING

EVALUATION:

1. What is the symbol for correspondence?

2. What is the symbol for congruency?

3. What does CPCTC stand for when working with congruent triangles?

Name the corresponding sides and angles of the given triangles below

Many structures have straight beams that meet at joints. You can use models to

explore ways to strengthen joints.

●Cut seven cardboard strips about 6 in. by 1/2 in.

Make a square frame and triangular frame.

Staple across the joints, as shown.

●With your fingertips, hold each model flat on a desk or table

and try to change its shape. Which is more stable?

●Cut another cardboard strip and use it to form a brace for the square

frame. Is it more rigid? Why do you think the brace works?

" For the things of this world

can not be known

without the

knowledge of mathematics"

Roger Bacon