Lesson Plan in MathematicsGrade 5

Grade V – Acacia (7:50-8:50)

I. Learning Objectives

Cognitive: Visualize similarity of polygonsIdentify similar polygons

Psychomotor: Illustrate similar polygonsAffective: Show enthusiasm in performing any assigned task

II. Learning Content

Skills: Visualizing similarity of polygonsIdentifying similar polygons

Reference: BEC-PELC III.3 Mathematics 5: Mathematics for the Better Future, Coronel And bamba, pp. 226-231

Materials: examples of similar polygons, PPT presentationValue: orderliness

III. Learning Experiences

A. Preparatory Activities

1. Drill a. Post models of different polygons on the board and ask the pupils which of these polygons have the same shape. Ask them to name the

different polygons posted on the board.

2. Review

a. Have the pupils explain when two angles or line segments are congruent?

3. Motivation

a. Show the class objects of various sizes. Ask the pupils to arrange these from smallest to biggest.

B. Developmental Activities

1. Presentation

a. Have the pupils observed the pictures below.

b. Ask: Is the smiley in one picture the same smiley in the otherpicture? What makes the pictures different?

c. Have the pupils compare the triangles and the octagons. Ask: How are the figures like the two pictures first observed?

d. Introduce the term similar to describe each pair of triangles and each

pair of octagons. Have them observe these figures.

Activity 1.

Tell whether the pairs of polygons are similar or not. Why or why not?

Ask the pupils: Answer with yes or no, explain your answer.

1. Do similar polygons have the same shape?2. Do similar polygons have the same size?3. Are all congruent polygons similar?4. Are all similar polygons congruent?

e. Have the pupils observe the two quadrilaterals below.

Ask: Are the corresponding angles congruent? Explain why these two figures are similar.

f. Have the pupils read the problem.

Follow these steps:

1. Draw GH 4 cm long since the length must be doubled. 2. Mark two points 2 cm directly above points G and H since the width must

be doubled. Label these points F and E. 3. Draw GF, FE, and EH. 4. Using a protractor, check if the angles are congruent to those of the

original.

Ask: Are rectangle ABCD and rectangle FEHG now similar?

3. Generalization When do you say that two polygons are similar?

Two polygons are similar if: a. have the same shape but may have different size.. b. their corresponding angles are congruent and their corresponding sides have equal ratios.4. Application

Willy wants to draw a rectangle similar to the one at the left. Mrs. Reyes, his teacher, suggests that he double the length of each side. How can Willy draw a rectangle?

1. Look at the things inside the classroom and identify the similar sides or faces.

a. books c. tablesb. chalkboard d. walls

2. Fine pairs of figures in your classroom that show similarity.

IV. Evaluation

Draw a polygon similar to each polygon. Use the indicated increase in the length ofeach side.

1. increase length two times 2. Increase length 3 times

3. increase length four times

V. Assignment

Determine whether the polygons in each pair are similar.

1. 2.

3.