标题: one math question? [打印本页] 作者: falcons 时间: 2005-8-27 05:32 标题: one math question?
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作者: assfgrtrtr 时间: 2005-8-27 05:56
