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Area of an equilateral triangle=squareroot(3)/4*a^2
inthe above formula a is side of an equilateral triangle
according to the question area of an equilateral triangle=57 cm^2
squareroot(3)/4*a^2=57
multiplying both sides by 4/root(3)
root(3)/4*4/root(3)*a^2=57*4/1.732 (root(3)=1.732)
after cancilation
a^2=228/1.732
a^2=131.63
a=root(131.63)
a=11.47
now the perimeter of equilateral triangle=root(3)/2*a
=1.732/2*(11.47)
=0.866*11.47
=9.93cm
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