Question 1205077
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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.



<pre>
The proportion should relate the areas of the mats, OBVIOUSLY.

    {{{3/x}}} = {{{(pi*r^2)/(pi*R^2)}}},

or 

    {{{3/x}}} = {{{((1.5/2)^2)/((2.5/2)^2)}}}.


From this proportion

    x = {{{3*(2.5^2/1.5^2)}}} = 8.333.


Round it to the closest greater integer number to have a necessary margin.


<U>ANSWER</U>.  9 bundles of grass is needed.
</pre>

Solved.