我数学真差啊，几道prep题大家帮帮忙，谢谢

steinlala

谢谢sd呀，真是大好人。
那个圆弧题的原题是这样的：
给一个图，圆内接等边三角形ABC, the length of arc ABC is 24, what is the approximate diameter of the circle.

-- by 会员 steinlala (2011/3/22 7:41:33)

In that case, the circumference = 1.5*24 = 36 = pai * diameter.

-- by 会员 sdcar2010 (2011/3/22 8:38:24)

想问下，那个1.5是怎么来的？谢谢

sdcar2010

The three vertice of the triangle simply divide the circle into three equal arches. Arch ABC is 2/3 of the whole circumference.