标题: shuxue jj13 [打印本页] 作者: gracezhang 时间: 2011-12-30 02:23 标题: shuxue jj13 为什么是4（2+根号3）R^2?作者: sdcar2010 时间: 2011-12-30 02:39
Connect all three centers of the circles and you will have a triangle with equal sides. The height of that triangle (whose side measures 2R) plus 2 R is the length of the shorter side of the rectangle. The longer side of the rectangle is 4 R.作者: gracezhang 时间: 2011-12-30 05:49
thanks very helpful