Question 1029124: What is the total surface area of the new tower?
http://imgur.com/S6CASrU
http://imgur.com/r5jzIXv
Found 2 solutions by addingup, MathTherapy:
Answer by addingup(3677)   (Show Source):
You can put this solution on YOUR website! Both cylinders have a height of 18".
Radius:
top: 18
bottom: 36
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Area of the top of the small cylinder:
A= Pi*(d/2)^2 = 254.50
Area of the bottom of the big cylinder:
A = Pi*(d/2)^2 = 1,017.88
Area of the top of the big cylinder:
1,017.88-254.50 = 763.38
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Area of the perimeter of the small cylinder (note imagined you peeled a label that wrapped perfectly around the cylinder. Once you take it out you realize the label is a rectangle, so the formula for rectangles applies here):
Length: d*Pi = 56.55
Width: 18
Area: L*W = 56.55*18= 1,017.90
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Big cylinder:
Length: d*Pi = 113.10
Width: 18
Area: L*W = 2,035.80
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Total area (adding from the bottom up):
1,017.88 . . Bottom big cyl
2,035.80 . . Area wrap-around big cyl
763.38 . . . Area top big cyl (area minus area of small cyl sitting on top)
1,017.90 . . Area wrap-around small cyl
254.50 . . . Area top small cyl
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5,089.46 square inches is the total area
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Answer by MathTherapy(10552)  (Show Source):
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