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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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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) • Page 271: • 5c, 8c, 10, 11, 14 8ab 5c, 6c, 7c, 8c, 10, 11 5a, 6, 7, 8b, 10
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 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. • 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
Show Me What You Know# 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) • Page 278-279: • 2, 15, 16, 18, 19 10 2, 3a, 6, 11, 12, 13 1, 2, 3a, 5, 6, 7a, 9
Secret to the perfect pancake is discovered http://phys.org/news/2014-03-secret-pancake.html#ajTabs
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