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Find the area of an equilateral triangle inscribed in a circle with a circumference of 8 Pi cm.

 Feb 9, 2018
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We need to find the radius of the circle....so we have that

 

8 pi    =  2pi * r       divide both sides by 2pi

 

4 cm  = r

 

 

 

(1/3)  of the area of this triangle can be found  as  :

 

(1/2) r^2 sin (120° )  =

 

(1/2) 4^2 * √3/2  =

 

4√3  cm^2

 

So....3 times this is  just

 

12√3  cm^2  ≈  20.78 cm^2

 

 

cool cool cool

 Feb 10, 2018

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