Please help, (finding the vol. and S.A. of a hemisphere)

fallinbehind

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Oct 9, 2005
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This problem says:
The people of the arctic use blocks of snow to build igloos in the shape of hemispheres, or half of a sphere. Suppose the igloo is 15 feet in diameter.

a.) find the amount of floor space to the nearest square foot

b.) find the surface area to the nearest square foot and the volume to the nearest square foot

I can find the volume and surface area of a sphere in pi feet cubed/squared, but I don't know how to do this for hemispheres

I also don't understand how to find the floor space

Please help, I'm having trouble staying caught up this year
 
A hemisphere is half a sphere so it has half the SA and volume.
The floor is a circle with the radius of the sphere.
 
The area of a circle is
A=pi*r^2 or
A=pi*d^2/4
d=15, r=7.5
Its a strange book that gives the surface of a sphere but not the area of a circle. :twisted:
 
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