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2010 AMC 8 Problems/Problem 18

Revision as of 22:32, 15 May 2012 by WolfOfAtlantis (talk | contribs) (Created page with "The ratio of AD to AB is 3:2 and AB=30 inches. <math>If 30=2, then x=3. x=45. </math> The area of the rectangle is <math>45*30= 1350</math>. The semicircles, when combined, have...")
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The ratio of AD to AB is 3:2 and AB=30 inches. $If 30=2, then x=3. x=45.$ The area of the rectangle is $45*30= 1350$.

The semicircles, when combined, have the area of a regular circle. Radius is 15 ($30/2=15$, for the record). Area of a circle is $\pi r^2$ , so it's equal to 225$\pi$

$1350/225 \pi$ is equivalent to $6/ \pi$ [1] The image given in the test is given above for reference.

Answer is $\box{C: 6:\pi}$ (Error compiling LaTeX. Unknown error_msg)

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