Answer: Choice C.
This is the same as writing 36*sqrt(3)
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Work Shown:
x = 12 = side length of equilateral triangle
A = area of equilateral triangle
A = 0.25*sqrt(3)*x^2
A = 0.25*sqrt(3)*12^2
A = 0.25*sqrt(3)*144
A = 0.25*144*sqrt(3)
A = 36*sqrt(3) .... answer is choice C
Side note: the area approximates to 62.354 square units.