SOLUTION: I need to calculate the number of roses necessary to cover an 8" globe. The roses would average 2" in width.

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Question 153186: I need to calculate the number of roses necessary to cover an 8" globe. The roses would average 2" in width.
Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
By "8-inch globe", I assume that you mean the diameter of the globe (sphere) is 8 inche!?
And by the roses' average width of 2" I assume that the diameter of the rose averages 2 inches!
So, let's find the surface area of the 8" globe (sphere).
The surface area of a sphere is given by:
A%5Bg%5D+=+pi%2AD%5E2 ...and the area of a rose, which approximates a circle, is given by:
A%5Br%5D+=+pi%2Ar%5E2 or A%5Br%5D+=+pi%2A%28D%2F2%29%5E2 = pi%2AD%5E2%2F4
So, for the 8" globe, we have:
A%5Bg%5D+=+pi%2A%288%29%5E2
A%5Bg%5D+=+64%2Apisq.in....and for the roses, we have:
A%5Br%5D+=+pi%2A%282%29%5E2%2F4
A%5Br%5D+=+pisq.in.
Now you want to know many times will the area of the rose (pisq.in.) go into the area of the globe (64%2Apisq.in.)? So we divide the globe area by the rose area.
64%2Across%28pi%29%2Fcross%28pi%29+=+64
You would need about 64 2"-roses to cover the surface of an 8"-globe.