4'5 Area of a Circle

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4.5 Area of a Circle
The area is the amount of space the circle takes
up
If we know the diameter or the radius, we can
calculate the area. Formula Area p x radius x
radius Or A p x r x r which can also be written
as A p r2
2
Area Example
What is the Area? A p x r x r A 3.14 x 2 cm x
2 cm A 12.56 cm2 The area is 12.56 cm2
2 cm
4 cm
Your turn What is the area of the circle below?
6 cm
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Area Practice
What is the area? A p r2 We have been given the
diameter but need the radius ??? Remember r d
2 so the radius is 12 cm 2 6 cm A 3.14 x 6
cm x 6 cm A 113.04 cm2
12 cm
4
Your Turn
Calculate the area of the circles below
5 cm
6 cm
24.6 m