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Grade 7:  The Learning Equation Math

31.01 Circle Measurement

 Measurement Refresher pp 54-55

Learning Outcomes:

The student will:

Lesson on Circumference of a Circle

Circumference

 r = radiusd = diameter C = Circumference p = C/d = 3.14...

source:  Circle Notes

 Area C = 2pr C/2 = pr The circle (C = 2pr) shown has the area shaded blue and red. Consider the sectors as pieces joined on the circumference, able to be opened out in the two halves. By inter-weaving the sectors, we get the picture shown below where: the base of the parallelogram is half of the circumference (pr) and the height is the radius (r) base(b) parallelogram A = bh height(h) = r A = bh = pr(r) =  pr2 Source:  Lesson Plan - Area of a circle

Drag the handle to change the size of the radius and diameter. Study the change in circumference and area as you do so.

Review:

Circle Properties

MathsNet Dynamic Geometry

MathsNet Dynamic Geometry

Enrichment:

The Expanding Circle

9 Point Circle

 Key Terms: A-E F-J K-O P-R S-Z

circle, diameter, radius, circumference, pi, nonrepeating, decimal, polygon

Prerequisite Skills:

Multiplication of Decimals:  Grade 7 Lesson 12.01

Perimeter and Area:   Grade 8 Lesson 32.03

Patterns and Relations:   Grade 7 Lesson 21.02

Linear Equations 1:  Grade 7 Lesson 22.02

Linear Equations 2:  Grade 7 Lesson 22.03

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