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Find the area of an equilateral triangle inscribed in a circle with a circumference of 18 Pi cm.

 Dec 3, 2020
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The radius of the  circle can be found as

 

18pi  = 2pi * r

18pi / (2pi)  =  r   = 9

 

We can divide the  equilateral triangle into three congruent triangles.....the area of  of of these triangles is given by

 

(1/2) r^2  *sqrt (3) / 2  =    (1/2) 9^2  *  sqrt (3)  / 2  =   81 sqrt  (3) / 4  cm^2

 

So....the area of the equilateral triangle  =    3 (81)sqrt (3) / 4  cm^2  =  (243)sqrt (3) / 4  cm^2

 

 

cool cool cool

 Dec 3, 2020
edited by CPhill  Dec 3, 2020
edited by CPhill  Dec 3, 2020

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