one math question?

falcons

I think answer should be B. What do you think?
Question # 8
A circle is circumscribed about an equilateral triangle of side 'a'. The diameter of the circle is

(A) a v3 (where v3 denotes 'root-3')

(B) a / v3

(C) 2a/ v3

(D) 2 v(3a)

(E) 3 v(a)

Your Answer : B
Actual Answer : C

Explanation
Let R be the circumradius, then,
Area of the triangle = Product of sides of a triangle/4R.
Here, side of equilateral triangle = a. Area of equilateral triangle = 3^½/4 a². Therefore a * a * a/4R = (3^½/4)a². R = a/3^½. Diameter = 2R = 2a/3^½.

Hence (C) is the correct answer

assfgrtrtr

不是用面积做的，而是利用余弦定理做的，答案是B

xiongxiong88

ding!!!!!!!!!!