8/9/2019 p522 527 Unit 9 L6 Meas Area Unay

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Elicit

Engage

Lesson 6

Visualizing Area of a Circle

We learned that area is the number of square units it takes to cover a surface.

What are the areas of the square and rectangle below?

(Illustrate a square and rectangle. Illustrate also ‘square unit’ or a small square beside

the square and rectangle. This is illustrated below.)

ow man! square units does it take to cover surface of the square? ow about thearea of the rectangle?

 Pause & Answer 

ow well do I know this idea?

ow "re"ared am I to move further to this lesson?

#oes a circle have an area also?$ut%out a circle and a square using a construction "a"er as shown below.

10

a squareunit

8/9/2019 p522 527 Unit 9 L6 Meas Area Unay

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Explore

Which of the two has a larger area? Wh!?

 Pause & Answer 

What do I want to know about the area of a circle?What do I want to learn this?

The circle is enclosed inside a & ' & grid. $an !ou see the small squares inside the

circle? What do !ou think is area of the circle below in terms of the number of squares?

et us count the number of small squares inside the circle and combine the "arts

of the remaining squares.

ow big is the surface of the circle in terms square units?

reasonable estimate for the area of the circle is * square units.

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8/9/2019 p522 527 Unit 9 L6 Meas Area Unay

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Explain

Elaborate

et’s have another one. +ach small square is , cm square units. What are the areas

of the three circles?

r3r2r1

CBA

ook closel! at the radius of each circle. What ha""ens to the area of the circle as

the radius increases?

#iscuss the ideas !ou learned with a "artner. -ill in the table below.

Things that I e"ected to learn Things that I have learned

/elow are the ideas that !ou learned in this lesson.

rea is the number of square units it takes to cover a surface.

The area of a circle can be estimated by counting unit squares and parts of

 squares that cover the surface of the circle.

The area of the circle increases as its radius increases.

0et the 1hili""ine "eso coins of different values. 1ut the coins above the grid

 below. Then estimate the area of each coin.

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8/9/2019 p522 527 Unit 9 L6 Meas Area Unay

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Enrich

Evaluate

What ha""ens to the value of coin as the area increases? What can we learn about

the monetar! s!stem of our coins?

The area of our coins increase as their values increase.

2earch more information about the lesson to enrich what !ou have 3ust learned.

,. The website below is an interactive mani"ulative to show the area of a circle.htt"455www.matho"enref.com5circlearea.html

6. 2urf the internet. ook for more information and eercises about the adding fractions andmied numbers that !ou have 3ust learned. 1rovide the following information taken from

!our source.

• What information did !ou get?

• Where did !ou get this information?

• What eercises did !ou find? In what website did !ou get them?

• What additional information did !ou learn?

Test your KNOWLEDGE & UNDERSTANDING

Write True on the blank if the statement is correct7 if not write a reason wh! it is

incorrect.

 888888,. ll "lane figures have area.

13

(Illustrate the

different values of 

coins4 1,97 1:7

1,7 and 6:cents)

8/9/2019 p522 527 Unit 9 L6 Meas Area Unay

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Expand

 8888886. The area of the circle decreases as the radius becomes smaller.

 888888&. circle with a longer radius has a smaller area.

 888888;. The area of a circle can be estimated b! counting the squares. 888888:. The measure of the area of a circle is in square units.

Show your SKILLS, PRODUCT or PERFORMANCE

. +stimate the area of the shaded "art using !our knowledge about the area of a circle.

$ount the number of square units of the shaded "art.

(Illustrate the following figures as shown below.)

,. 6.

&.

 Pause & Answer 

Are you happy with the result of your evaluation? Why?What concepts are clear to you?

What concepts are still not clear to you?

,. <sing a com"ass and a gra"hing "a"er7 draw a circle whose area is indicated

 below.

a. ,= square unitsb. 6: square units

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Reflect

c. &= square units

6. >easure and com"are the diameter of each circle.

&. What can !ou sa! about the area of a circle as the diameter gets longer?

In !our notebook7 write !our reflection of !our lesson using the following

questions as !our guide.

What parts of

the

lesson do I likethe most ? Why?

What partsof the

lesson do I 

like the least ?Why?

What is themost 

challenging 

 part  in thislesson? Why?

 In what  situation/s

do I find 

this lesson most 

useful?

What isthe most desirable

value or attitude

that I have

developed in this

lesson?

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