SOLUTION: Can anyone help with this word problem...Thank you. For a holiday party, Marcus is making a seven-layer torte, which consists of seven 9-inch diameter cake layers with a cream t

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Question 73617: Can anyone help with this word problem...Thank you.
For a holiday party, Marcus is making a seven-layer torte, which consists of seven 9-inch diameter cake layers with a cream topping on each layer. He knows that one recipe of cream will cover 65 square inches of cake. How many batches of the topping must he make to complete his torte? (Use p = 3.14 as an approximate value)

Answer by bucky(2189) About Me  (Show Source):
You can put this solution on YOUR website!
The top of each layer on this cake is a circle with a 9 inch diameter. The formula for
finding the area of a circle when you know the diameter is:
.
A+=+%28pi%29%2AD%5E2%2F4
.
where A is the area (in this problem the area will be in square inches), pi is 3.14, and
D is the diameter (in this problem D is 9 inches).
.
Since we need to find the Area we can substitute 9 for D in the formula to get:
.
A+=+%28pi%29%2A9%5E2%2F4+=+%283.14%29%2A81%2F4
.
A little calculator work on the right side tells you the Area of the top of a single layer
is 63.585 square inches. But there are 7 layers, so we have to multiply this answer by 7
to find that there are a total of 63.585%2A7+=+445.095 square inches that need to be
"creamed." Since a single batch covers 65 square inches, we divide the 445.095 square inches
of area to be covered by the 65 square inches of coverage in a batch to find that Marcus
will need 6.85 batches. I imagine that he will just mix 7 batches and eat what little is
left over.
.
Hope this helps you understand the problem a little better.