1. LESSON PLAN
Level : Junior High School
Subject : Mathematics
Class : IX
Semester : I
Topic : Similarity and Congruence
Standard Competence : Understanding the similarity of
figures and the use of it in
problem solving
Time Allocation : 2 x 40 minutes
Standard Competence
Understanding the similarity of figures and the use of it in problem solving
Basic Competence
Identifying similar and congruent figures
Indicators
1. Cognitive
a. Determining whether or not two figures are similar
b. Mentioning the pairs of similar figures
c. Solving problems dealing with similar figures
2. Psychomotor
a. Drawing two similar figures
b. Drawing two figures which are not similar

2. 3. Affective
a. Characterized Behaviors
Responsibility, willingness to help others, and the feel of never
surrender.
b. Social Skills
Team working, be active in discussion, be brave to deliver ideas, be
open to criticisms, and be able to give others the opportunity to speak
up.
Learning Objectives
1. Cognitive
a. Given two figures, students are supposed to be able to determine
whether or not the figures are similar
b. Given some problems dealing with the concept of similarity, students
are supposed to be able to solve them.
2. Psychomotor
a. After learning about similar figures, students are supposed to be able
to draw a pair of similar figures.
b. After learning about similar figure, students are supposed to be able to
draw a pair of figures which are not similar.
3. Affective
a. Characterized Behaviors
Being involved in a student-centered learning activities, students are
supposed to be able to show responsibility, wilingness to help others,
and the feel of never surrender at least be judged as “Starts to appear”.
b. Social Skills
Being involved in a student-centered learning activities, students are
supposed to be able to work in teams, be active in discussion, be open

3. to criticisms, and be able to give others the opportunity to speak up at
least be judged as “In Progress”.
Learning Model
Learning Model : Problem-Based Instruction
Learning Activities
 Introduction (± 10 minutes)
1. Phase 1.Students on the issue orientation
o Teacher leads the students to recall what they have learned from
the previous meeting. These questions may help: “What did you
learn in the last meeting? Is it about similarity? What are the
properties of two similar figures? When are two figures said to be
similar?”
o Motivation: Teacher gives an illustration of an event taken from
daily life related to the concept of similarity. Here is one of the
possible illustrations.
All of you must have allowance or
pocket money. Your parents most
likely give you the money at the
beginning of the week. Now, take a
look at the money that you have in
your pocket right now! Do you have
any coins with you? Last meeting
we had studied about similarity and
the properties of two similar figures. Now, what do you think about the coins? Are
they similar? Why are they or why are not they? And now, do you have cash? In
what shape are they? Are they similar? Why are they or why are not they?
o Teacher communicates the outlines of basic competence and
indicator that will be learnt.

4. o Teacher leads students to recall the lesson that had been learnt in
the previous meeting e.g. “when are two figures said to be similar?
What are the requirements for two figures to be congruent?”.
o Teacher may „gradually‟ lead students to deal with the topic which
is going to be delivered in the meeting.
 Main Activities (± 70 minutes)
2. Phase 2.Organize students to learn
o In this stage, teacher can divide students into several learning
groups containing three to four students.
o Further, teacher can pose a problem dealing with similarity (the
problems are available in the worksheet).
3. Phase 3.Guide theinvestigationof individualand group
o Teacher guides and assists students to work in groups to solve the
problems.
4. Phase 4.Develop and present the work
o Teacher helps students to present the work (the result of the
discussion) in front of the class.
5. Phase 5.Analyze and evaluate the problem solving process
o In this phase, teacher may ask several groups to present their work.
o Teacher emphasizes that the other student who do not get the
chance to present their work shoul give their opinion regarding to
the presenting teams‟ works. Here, teacher leads the discussion and
helps students to settle the problem by getting closer to the right
answer.
Note: Teacher can also modify the learning activities by posing more than one
problem. In modifying this, teacher may provide more than one worksheet. Then,
the learning activities will be going back to the second step until the fifth step.
This can be repeated until all the problems have been settled. Here, I suggest to
use two or three problems in two or three worksheets.
 Closure (± 10 minutes)
o Teacher leads students to conclude what they have learned that day.

5. o Teacher might ask the students to write a reflection regarding to the
lesson and the learning activities that they have experienced that
day.
o Teacher may also gives homework for students to practice.
o Teacher closes the lesson that day.
Assessment
The assessment can be done by assessing the student performance during the
project presentation, the content of the work presented, and also the activities
within the groups. The students who do not present their work are assessed by the
worksheet/s that have/s been completed.