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Circles (Unit 8). AC DR Area Circumference Diameter Radius. Circles (Unit 8). Video – Learn Alberta. http://www.learnalberta.ca/content/mejhm/index.html ?l=0&ID1=AB.MATH.JR.SHAP&ID2=AB.MATH.JR.SHAP.CIRC&lesson=html/ video_interactives/circles/circlesSmall.html.

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Circles(Unit 8)


AC DR

Area Circumference Diameter Radius


Circles(Unit 8)

  • Video – Learn Alberta

  • http://www.learnalberta.ca/content/mejhm/index.html

  • ?l=0&ID1=AB.MATH.JR.SHAP&ID2=AB.MATH.JR.SHAP.CIRC&lesson=html/

  • video_interactives/circles/circlesSmall.html


Construct Circles(Unit 8)

Student outcome: I will be able to describe the relationship of radius, diameter and circumference

  • Use your compass to draw a circle…Use a ruler to find your radius first!

Radius

Distance from the centre of the circle to the outside edge…represented by “r”

Diameter

Distance across a circle through its centre…represented by “d”


Construct Circles(Unit 8)

Student Outcome: I will be able to describe the relationship between radius, diameter and circumference

  • Question…

  • How can you find the diameter if you are given the radius?

d = r x 2


Construct Circles(Unit 8)

Student Outcome: I will be able to describe the relationship between radius, diameter

  • Question…

  • How can you find the radius if you are given the diameter?

r = d ÷ 2


Let’s Construct Circles

  • Can you design the Olympic rings using a compass??


Let’s Construct Circles

  • Can you design the Olympic rings using a compass??

Rubric – Olympic Rings Rubric – Olympic rings

5 exact rings /5 5 exact rings /5

Parallel /2 Parallel /2

Straight Lines /3 Straight Lines /3

Spacing /Overlap /3 Spacing/Overlap /3

Neatness /2 Neatness /2

Total /15 Total /15


Practice (Homework)

  • Complete questions on pages…

  • Page 271:

  • # 5ab, 6ab, 7ac, 8c, 10,

  • Extend #14, 15


Circumference of a Circle

Student outcome: I will be able to describe the relationship of radius, diameter and circumference

  • Circumference: is the distance (perimeter) around a circle.

  • Steps:

  • Wrap a piece of string around the objects circumference

  • Then measure the string along the side of a metre stick.

  • Then measure the diameter of your object and relate it to the circumference.

Find The Circumference of Objects!


Circumference of a Circle

Student outcome: I will understand radius, diameter, circumference relationships.

  • Circumference: is the distance (perimeter) around a circle.

Find The Circumference of Objects!

  • What is the relationship between the diameter and circumference of a circle?


Circumference of a Circle

Student outcome: I will understand radius, diameter, circumference relationships.

  • Circumference: is the distance (perimeter) around a circle.

  • What is the relationship between the diameter and circumference of a circle?

  • ∏ is very close to 3 (friendly number)

C = 3 x d (estimated)

C = ∏ x d (actual)

  • The “∏” is known as pi and is known as 3.14

http://www.learnalberta.ca/content/memg/index.html?term=Division03/Circumference/index.html


Circumference of a Circle

Student outcome: I will understand radius, diameter, circumference relationships

  • Circumference: is the distance (perimeter) around a circle.

  • The “∏” is known as pi and is known as 3.14


Circumference of a Circle

Student outcome: I will understand radius, diameter, circumference relationships

  • Circumference: is the distance (perimeter) around a circle.


Circumference of a Circle

Student outcome: I will understand radius, diameter, circumference relationships

  • Circumference: is the distance (perimeter) around a circle.

  • The “∏” is known as pi and is known as 3.14


Practical Quiz # 1

  • The “∏” is known as pi and is known as 3.14


Circumference of a Circle

  • Did you KNOW?

  • The traditional Plains Indian powwow is an annual

  • celebration. People gather together for storytelling, singing,

  • dancing and feasting. The powwow grounds are circles and

  • the performers dance around the circle in a clockwise

  • direction. How would you determine the distance a dancer

  • travels in one complete trip around the circle?


Circumference of a Circle

Student outcome: I will understand radius, diameter, circumference relationships

  • PROBLEM:

  • What if you were given the “radius.” Then how would you find

  • the circumference? (Remember...before we multiplied the diameter by 3)

  • The “∏” is known as pi and is known as 3.14


Practice (Homework)

  • Complete questions on pages…

  • Page 278-279:

  • # 3ab, 6, 7ab, 10, 11, 17 (Good Luck)

  • Extend #16, 18, 19


Practical Quiz #2

  • Using a compass, design a 3 level (snowball) snowman.

  • One snowball has a radius of 2 cm

  • One snowball has a radius of 3 cm

  • One snowball has a diameter of 3 cm


Areaof a Circle

Area means the total amount of space inside of a circle (or any shape).

  • Try to come up with an equation for a circle using the hints given...

  • What are the hints?

5 m


Areaof a Circle

Area Equation is…

Answer is…there are roughly 3 squares (l x w) that fit into a circles. The remaining area outside of the circles roughly make up the area in the 4th part of the circle.

Actual Area Equation:

Area = ∏r ²

5 m


Areaof a Circle

Student outcome: I will be able to solve the area of a circle.


Area of a circle student outcome i will be able to solve the area of a circle

Show all your work...complete one step at a time!

Area of a CircleStudent outcome: I will be able to solve the area of a circle.


Practice (Homework)

  • Complete questions on pages…

  • Page 285-286:

  • # 4ab, 6, 9ab, 11, 15, 19 (Good Luck!)

  • Extend # 18, 20


Practical Quiz # 3

  • The “∏” is known as pi and is known as 3.14


Tattoo Me

  • Create a tattoo based on a circle(s)

http://www.arcvillage.org/KIDSTUFF/crop%20circle%20designs.htm


Tattoo Me

  • Create a tattoo based on a circle(s)

RUBRIC

Circumference /1

Diameter /1

Radius /1

Area /1

Colored /3

Neatness /3

Originality /3

TOTAL /13


Tattoo Me

  • Create a tattoo based on a circle(s)


Tatoo Me

  • Create art work based on a circle(s)


What is a “Circle Graph”

Student outcome: I will be able to read a circle graph.

  • Circle Graph:

  • a graph that

  • represents data using

  • sections of a circle

  • Sector:

  • a section of a circle

  • formed by two radii

  • and the arc of the

  • edge of a circle, which

  • connect the radii

http://www.learnalberta.ca/content/memg/index.html?term=Division03/Circle_Graph/index.html


Interpret Circle Graphs

Student outcome: I will be able to read a circle graph.

  • What is the graph about?

  • What do the different sectors represent?

  • What percent does Mrs. Bosch run?

  • What percent do the kids and Mr. Bosch represent?

  • What do all the sectors add up to be (percent wise)?


Interpret Circle Graphs

Student outcome: I will be able to read a circle graph.

  • What is the graph about?

  • What do the different sectors represent?

  • If you have a cat?

  • What are your chances of being a smart kid?

  • What are Mr. Bosch’s chances of being a smart kid?


Practice (Homework)

  • Complete questions on pages…

  • Page 290-291:

  • # 3, 5, 7, and 8


Create Circle Graphs

Student outcome: I will be able to build a circle graph.

  • You will need…

  • Ruler Protractor Compass Pencil Crayons

  • Construct a circle graph with a radius of 8 cm.

  • Create the circle

  • Questions:

  • a) What is the diameter?

  • b) How many degrees are in the top ½ of the circle?

  • c) How many degrees are in the bottom ½ of the circle?

  • d) What is the sum of the central angles of a circle?

8 cm


Create Circle Graphs

Student outcome: I will be able to build a circle graph.

  • Complete a Class Survey on Types of Pets!

  • You can only select ONE of the animals mentioned above.

  • Then complete the chart above as a class and work

  • with a partner to create your “Circle Graph.”


Create Circle Graphs

Student outcome: I will be able to build a circle graph.

  • How do we find the “degrees” of something?

  • % of 360° decimal x 360°

  • Example: 45% x 360°

  • 0.45 x 360° = 162°


Create Circle Graphs

Student outcome: I will be able to build a circle graph.

  • Results of Class Survey on Types of Pets!

Cat ( %)

Dog ( %)

Bird ( %)

Fish ( %)

Other ( %)


Create Circle Graphs

Student outcome: I will be able to build a circle graph.

  • Create your OWN survey! (must have 5 choices)

  • Once you’ve completed your data then complete circle

  • graph…make sure to have a LEGEND! Make sure the people

  • you survey only select ONE of the choices!


Unit Review

  • See the “JEOPARDY” game in the Math 7 File…

  • Unit Review Questions:

  • Page 298-299:

  • All questions except #10, 22


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