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Grade 7:  The Learning Equation Math

31.02 Circle Problems

 Measurement Refresher pp 56-57

Learning Outcomes:

The student will:

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.

 Circle Calulator Enter a value in for one of the following Click the Enter p = C/d = 3.14... Radius(r): cm Diameter(d): cm Circumference(C): cm Area(A): cm2

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

diameter, radius, circumference, area, dimensions, perimeter, trapezoid, mass, volume

Prerequisite Skills:

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Comments to:  Jim Reed
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