LESSON PLANLevel : Junior High SchoolSubject : MathematicsClass : IXSemester : ITopic : Geometry and MeasurementStandard Competence : 1. Understanding the similarityof figures and the use in problemsolvingTime Allocation : 2 x 40 minutesStandard Competence1. Understanding the similarity of figures and the use in problem solvingBasic Competence1.2 Identifying the properties of two similar and congruent trianglesIndicators1. Identifying two congruent or incongruent figures by showing therequirements.2. Determining two congruent triangles.3. Determining the proportions of the sides of two congruent triangles.4. Mentioning the properties of two congruent triangles.5. Mentioning the requirements of two triangles to be congruent.6. Proving two congruent triangles.7. Distinguishing the concept of similarity from congruency.
Learning Objectives1. Given the general definition of congruency, students can identify twocongruent or incongruent figures from the models provided by teacherby showing the requirements.2. Given several pair of triangles, students are able to determine whetherthey are congruent or not.3. Given two congruent triangles, students can determine the proportionsof the sides of the two triangle.4. Students are able to mention the properties of two congruent triangles.5. Students are able to mention the requirements of two triangles to becongruent.6. Given two triangles, students can prove that they are congruent.7. After learning about similarity and congruency, students are supposedto be able to distinguish the concept of similarity from congruency.Learning ModelLearning Model : Conceptual TeachingLearning Approach : Direct PresentationLearning Method : Lecture Method, Question-Answer MethodLearning SourcesHandbookLearning MaterialsWhite board and board markersPowerPoint Presentation
Learning Activities Apperception (± 10 minutes)1. Phase 1. Clarify aims and establish seto Teacher communicates the outlines of basic competence andindicators that will be learnt.o Teacher leads students to recall the lesson that had been learnt inthe previous meeting.o Teacher prepares the material and sets students ready to learn. Main Activities (± 60 minutes)2. Phase 2. Input examples and nonexampleso Teacher names the concept being learnt and informs it to thestudents. In this case, the concept is congruency.o Teacher explains the general definition of congruency.o Teacher provides students several figures and asks studentswhether the figures are congruent or not.o Further, teacher provides students several pairs of congruenttriangles and asks students to determine the proportions of the sidesof the triangles.o Teacher leads students to mention the properties of two congruenttriangles.o Teacher then poses the conditions in which two triangles are said tobe congruent.o Students, by the guidance of the teacher, try to conclude andmention the requirements in which two triangles are said to becongruent.o If it is possible, teacher can provide more examples andnoexamples of congruent triangles by leading the students to givereason why the triangles are said to be congruent.3. Phase 3. Test for attainmento To check whether students have mastered the concept ofcongruency or have not, teacher can ask several students randomly.The questions can vary from determining whether two triangles are
congruent or not to rementioning the properties of two congruenttriangles and the requirements in which two triangles are said to becongruent.o Teacher then can give small quiz to the students to check theirunderstanding entirely. The questions in the quiz may vary fromproving that two triangles are congruent to providing their ownexamples and nonexamples of two congruent triangles with thereason/s.4. Phase 4. Analyze student thinking processes and integration oflearningo Teacher gets students to think about their own thinking processes,about what they have learnt from that meeting. Teacher can modifythis activity by asking students to summarize what they have learntthat day in a piece of paper without taking a look at the book or anyother sources. The only source of the summarization is studentunderstanding.o Teacher then collects student summarizations and informs thestudents that the score they get from the summarization willcontribute to their score of the quiz.o Teacher then leads the students to integrate this new concept (aboutcongruency) by relating this concept to the previous concept whichis similarity.o Teacher leads the students to again recall the concept of similarityand then to compare the concept of similarity with the concept offrequency.o Teacher helps students to distinguish the concept of similarity fromthe concept of congruency. Closure (± 10 minutes)o Teacher leads students to conclude what they have learnt that day,this can be modified by opening ‘question’ session.
o Teacher can also give homework to the students before closing thelesson. The homework can be provided by the teacher or by thebook students have.AssessmentThe assessment can be done by assessing the quiz given. In assessing thequiz, teacher should give feedback for each student.