Difference between revisions of "2018 AMC 12B Problems/Problem 8"

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==Problem ==
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#REDIRECT [[2018_AMC_10B_Problems/Problem_12]]
 
 
Line Segment <math>\overline{AB}</math> is a diameter of a circle with <math>AB = 24</math>. Point <math>C</math>, not equal to <math>A</math> or <math>B</math>, lies on the circle. As point <math>C</math> moves around the circle, the centroid (center of mass) of (insert triangle symbol)<math>ABC</math> traces out a closed curve missing two points. To the nearest positive integer, what is the area of the region bounded by this curve?
 
 
 
==Solution==
 
Draw the Median connecting C to the center O of the circle. Note that the centroid is 1/3 of the distance from O to C.
 
Thus, as C traces a circle of radius 12, the Centroid will trace a circle of radius 12/3=4.
 
 
 
The area of this circle is pi*4^2=16pi ~ 50.
 
 
 
==See Also==
 
{{AMC12 box|year=2018|ab=B|num-a=9|num-b=7}}
 
{{MAA Notice}}
 

Latest revision as of 13:21, 5 June 2023