A. Standard Competency: Understanding similarity in plane figures and

using it in problem solving

 

B. Basic Competency To identify similarity and congruency plane figuresC. Learning ObjectivesStudents will be able to:

- Requirements for two similar triangles

- Determine the ratio of the corresponding sides of two triangles and find the side’s lengths

-Determine requirements for two congruent triangles

Before learn about this topic, you must remember about :The properties of :- Quadrilateral ( Rectangle, rombus, square, kite,

parallelogram)- Triangular

SIMILARITIES AND CONGRUENCES

Keywords / keyterms:- Simlarity, similar- Photograph- Plane shape similarity- Congruence- Plane shape congruence- Triangular similarity- Triangular congruence

- Corresponding- Property/ properties- Ratio- Quadrilateral- Rectangle- Triangle- Triangular- Rectangular

1. The Similarity of Plane Shapes1.1 Students are introduced to the concept

similarity- Learn about similar figures- Learn about characteristics of similarity of

figures

Look at the following shapes. Are they the same or different ?

Properties of two similar figuresTwo figures are similar if the corresponding

angles have the same measure and the ratios of the lengths of corresponding sides are equal

Example : Rectangles ABCD ( 5x3) cm and EFGH (7,5 x4,5)cm

Are similar C

A B

D

N M

K L

3

5

7,5

4,5

Observe some figures below

4

3

5

6

10

8

5

5

6

6

10

10

3

3

Which ones are similar among the following shapes ?

Based on the following measurement of rectangles, find the ratio

between length and width of each rectangles. Determine which ones that the similar rectangles....Rectangles length width Ratio

ABCD 16 Cm 12 Cm ...........

PQRS 20 Cm 15 Cm ...........

KLMN 8 Cm 6 Cm ...........

NOPQ 6 Cm 3 Cm ............

WXYZ 12 Cm 10 Cm ............

BCDE ……….. ……….

QRST ……….. ………..

LMNO ……….. ………….

GHIJ ………… ………….

RSTU ………… …………….

MNOP …………… …………….

That’s all for this time……Please discuss with your friends. If you find a

problem discuss with your teacher…..Don’t get bored practicing……Where there is will there is a way…….

Good Luck……. be happy……