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tamara brings home from the fete a perfectly shperical balloon that has a radius of 115 cm.
a)what is the surface area of the balloon? answer correct to one decimal place?
b)after a few days the balloon deflates to a radius of 10cm. what has the surface area shrunk to?
c)if the surfce area shrinks to 1000cmsquare, what will the radius be? :roll:
 Jun 7, 2012

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 #1
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priscilla:

tamara brings home from the fete a perfectly shperical balloon that has a radius of 115 cm.
a)what is the surface area of the balloon? answer correct to one decimal place?
b)after a few days the balloon deflates to a radius of 10cm. what has the surface area shrunk to?
c)if the surfce area shrinks to 1000cmsquare, what will the radius be?

 Jun 7, 2012
 #2
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Guest:

radius of 115 cm


r=115

Guest:

a)what is the surface area of the balloon? answer correct to one decimal place?


A=4*Pi*r^2
[input]4*Pi*(115)^2[/input]
A=166190.3cm^2

Guest:

b)after a few days the balloon deflates to a radius of 10cm. what has the surface area shrunk to?


[input]4*Pi*(10)^2[/input]
A=1256.6cm^2

Guest:

c)if the surfce area shrinks to 1000cmsquare, what will the radius be?


A=4*Pi*r^2
A/(4*Pi)=r^2
r=sqrt( A/(4*Pi) )
[input]sqrt( 1000/(4*Pi) )[/input]
r=8.9cm
 Jun 7, 2012

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