1. LESSON PLAN
School : Junior High School
Subject : Mathematics
Grade/Semester : VIII/1
Time Allocation : 3 x 40’
Standard of Competence : 3. Use Pythagorean Theorem in problem solving
Basic Competencies : 3.1 Using Pythagorean Theorem to determine the length of
a right angled triangle sides
A. Indicators
Investigate the Pythagorean Theorem.
Solve daily life problem related to determine the length of a right angled triangle sides
by using Pythagorean Theorem.
B. Objectives
By working together, students are able to investigate the Pythagorean Theorem.
Students are able to solve daily life problem related to determine the length of a right
angled triangle sides by using Pythagorean Theorem.
C. Learning Contents
Pythagorean Theorem
D. Methods
Model : Cooperative learning, Group Investigation Approach
Method : Discussion
E. Teaching and Learning Activities
 Opening activities
a. Apperception: Students recall the material about square, square root, and triangle
that have been learnt in grade VII.
Phase 1: Clarify goals and establish set
b. Teacher clarifies the learning goals.
c. Teacher motivates students by using the example, such as: "Television as a media
of information has many advantages, one of that is able to visualize the
information directly. Television is produced in a variety of sizes. In general, the

2. size of the television is expressed in inches (1 inch = 2.54 cm), ranging from 14
inches, 21 inches, and 49 inches. TV size stated in inches is a diagonal long of the
television. Let's say you have a 21-inch television, if the width 16 inches, what is
the height? You can easily calculate the height of the television if you understand
the concept of the Pythagorean Theorem. "
 Main activities
Phase 2: Present information
d. Teacher presents information about Pythagorean Theorem to the students.
e. Teacher delivers instructions to students about the activities that will be conducted
at this meeting.
Phase 3: Organize students into learning teams
f. Teachers organize students into a group of 3-5 people and help the group make an
efficient transition.
Phase 4: Assist teamwork and study
Phase 1 GI: Selection a topics
g. Students choose specific subtopics which are in the general area of the problem
(Pythagorean Theorem) set by the teacher.
Phase 2 GI: Cooperative Planning
h. Students and teacher plan the learning procedures, tasks, and consistent purposes
of the chosen subtopics.
Phase 3 GI: Implementation
i. Students work with the group for implementing the learning plan with the help of
the worksheet.
j. Teacher guides and helps students study and manages the groups of students to
keep studying and working in their seats, also closely monitor the progress of each
group.
Pythagoras was a mathematician and Greek philosophy who lived during
the years 569-475 before CE. Pythagoras states that the quadratic
length of the hypotenuse of a right triangle is equal to the number
square of the length of the other sides. Do you believe it? We are going to
prove Pythagoras’ statement in our activities today.

3. Phase 4 GI: Analysis and synthesis
k. Students analyze and evaluate the information obtained on the third stage and
summarize the information as an interesting class presentation.
Phase 5: Test on the materials
Phase 5 GI: Presentation of final results
l. Every group presents the results of the investigation to the class in turn; other
groups can give comments, suggestions, or questions so students interact each
other and gain extensive knowledge about the topic.
m. Students and teacher evaluate the contribution of each group.
Phase 6: Provide recognition
n. Teacher gives reward or praise to the students of their learning outcomes.
 Closing activities
o. Teacher reminds students to study the next chapter.
F. Learning Resources
 Resource : Students Book
Students’ Worksheet
Internet
 Tools :Paper, Scissor, Glue, Pencil, Ruler.
G. Assessment
Technique : Written
Instrument : Essay
Example of Instrument:
1. A ladder isleaning on thewall.The distance between thelegs
of the ladder with thewall is2 metersand the distancebetween the groundand the
top ofladderis 8 meters. Calculate thelength ofladder!
2. The diagonallength ofa television is14 inch. If the height ofthe television
is 6inch, what is the width ofthe television?
3. Aship issailingto the west directionas far as11 km. Then, ship
turnto the southas far as8 km. Calculate thedistance ofthe shipfrom the starting
pointdeparture to the end point.
Rubric of Scoring

4. No. Answer Score
1. First, we need to draw the picture of ladder which is leaning
on the wall
Then, by using Pythagorean Theorem
BC² = AB² + AC²
BC² = 2² + 8²
BC =
=
=
= 2
So, the length of the ladder is 2 m.
10
10
10
5
Sub total score = 35
2. Suppose the television is drawn as rectangular ABCD.
Then, by using Pythagorean Theorem
AB² = AC² -BC²
AB² = 14² - 6²
BC =
=
=
= 4
So, the width of the television is 4 inch.
5
10
10
5
Sub total score = 30
8m
mm
2m
mm
A
m
m
m
B
m
m
C
m
m
A B
CD
14
4
6

5. 3. First, draw the picture
Then, by using Pythagorean Theorem
BC² = AB² + AC²
BC² = 8² + 11²
BC =
=
So, the distance from the starting point departure to the
endpoint is km.
10
10
10
5
Sub total score = 35
Total score = 100
A
B
C
11
1
8