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It takes about 3 bundles of grass to weave a circular mat of diameter 1½m.
How many bundles to the nearest bundle, does it take to weave a similar mat of diameter 2½m?
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The solution in the post by MathLover1 is INCORRECT.
I came to bring a correct solution.
The proportion should relate the areas of the mats, OBVIOUSLY.
= ,
or
= .
From this proportion
x = = 8.333.
Round it to the closest greater integer number to have a necessary margin.
ANSWER. 9 bundles of grass is needed.
Solved.