Circle Formulae 2

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Circle Formulae 2
The area of a circle Tandi Clausen-May
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or If you click too soon you will miss the best
bits.
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Click to see
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The area
of a circle
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Tandi Clausen-May
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We saw in Circle Formulae 1 that
Circumference
? Diameter
Now, what about the area?
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Imagine a circle made out of strands of
beads. Open it out.
Click to see the circle open
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Lets watch that again.
Click to see the circle open again
circumference
Its a triangle!
base circumference
height radius (half the diameter)
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We know how to find the area of a triangle.
radius (half the diameter)
circumference
Area of the triangle
Base Height 2
Circumference Radius 2
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Open out the circle, A triangle comes in
sight! Its base is the circumference. The radius
is its height.
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Open out the circle, A triangle comes in
sight! Its base is the circumference. The radius
is its height.
So now the circles area, Lets think, what could
that be? Its half of the circumference, Times
radius, you see!
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Summary
Circumference Radius 2
Area
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The End
Tandi Clausen-May