?l=0&ID1=AB.MATH.JR.SHAP&ID2=AB.MATH.JR.SHAP.CIRC&lesson=html/ 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) 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) Question… How can you find the diameter if you are given the radius? d = r x 2

Construct Circles (Unit 8) 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??

Practice (Homework) Page 271: # 5ab, 6ab, 7ac, 8c, 10, 14 (Good Luck) Complete questions on pages… Page 271: # 5ab, 6ab, 7ac, 8c, 10, 14 (Good Luck) Extend #14, 15

Circumference of a Circle Circumference: is the distance (perimeter) around a circle. Steps: Wrap a piece of string around the objects circumference...then cut it! 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! Circular Object Circumference Diameter How many diameters fit? Create an equation using “d”

Circumference of a Circle Circumference: is the distance (perimeter) around a circle. The “∏” is known as pie and is known as 3.14 Diameter Roughly 3 “d” equal “c” (3d = c) Circumference Actual Equation (∏d = c) http://www.learnalberta.ca/content/memg/index.html?term=Division03/Circumference/index.html

Circumference of a Circle Circumference: is the distance (perimeter) around a circle. The “∏” is known as pie and is known as 3.14 Diameter Roughly 3 “d” equal “c” (3d = c) Circumference Actual Equation (∏d = c) 5 12 35

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 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 pie and is known as 3.14 Radius Your Equation ( ) Circumference Actual Equation 2 7 12

Practice (Homework) # 3ab, 6, 7ab, 10, 11, 17 (Good Luck) Complete questions on pages… Page 278-279: # 3ab, 6, 7ab, 10, 11, 17 (Good Luck) Extend #16, 18, 19

Practical Quiz #1 Using a compass, design a 3 level (snowball) snowman. One snowball has a Diameter of 6 cm One snowball has a radius of 2 cm One snowball has a diameter of 3 cm

Area of 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

Area of 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

Area of a Circle Show all your work...complete one step at a time! Radius Estimate Area A =3 x r x r or A = 3r² Actual Area A = ∏r² 6 cm 8 cm 14 cm

Area of a Circle Show all your work...complete one step at a time! Diameter Find the “__________” Estimate Area (3 x r x r) Actual Area (∏r²) 6 cm 10 cm 13 cm

Practice (Homework) # 4ab, 6, 9ab, 11, 15, 19 (Good Luck!) Complete questions on pages… Page 285-286: # 4ab, 6, 9ab, 11, 15, 19 (Good Luck!) Extend # 18, 19, 20

Create a tattoo based on a circle(s) Tattoo Me Create a tattoo based on a circle(s) http://www.arcvillage.org/KIDSTUFF/crop%20circle%20designs.htm

Create a tattoo based on a circle(s) Tattoo Me Create a tattoo based on a circle(s)

Create art work based on a circle(s) Tatoo Me Create art work based on a circle(s)

What is a “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 What is the graph about? What do the different sectors represent? What percent does Mrs. Bosch run? What percent does Mr. Kittie and Mr. Bosch represent? What do all the sectors add up to be (percent wise)?

Interpret Circle Graphs 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) # 3, 5, 7, and 8 Page 290-291: Complete questions on pages… Page 290-291: # 3, 5, 7, and 8

Create Circle Graphs You will need… Ruler Protractor Compass Pencil Crayons Construct a circle graph with a radius of 8 cm. Create the circle Questions: How many degrees are in the top ½ of the circle? How many degrees are in the bottom ½ of the circle? What is the sum of the central angles of a circle? 8 cm

Create Circle Graphs 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.” Favourite House Pet Cat Dog Bird Fish Other Number of Students Fraction Percent Percent of 360°

Create Circle Graphs % of 360° decimal x 360° Example: 45% x 360° How do we find the “degrees” of something? % of 360° decimal x 360° Example: 45% x 360° 0.45 x 360° = 162°

Results of Class Survey on Types of Pets! Create Circle Graphs Results of Class Survey on Types of Pets! Cat ( %) Dog ( %) Bird ( %) Fish ( %) Other ( %)

Create Circle Graphs 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! ??? Number of Students Fraction Percent Percent of 360°

Unit Review Page 298-299: # 8a, 9b, 12ad, 13, 14, 18, 20 See the “JEOPARDY” game in the Math 7 File… Unit Review Questions: Page 298-299: # 8a, 9b, 12ad, 13, 14, 18, 20