Cast a cylindrical iron block with a base radius of 2cm and a height of 3cm2a into a cone with a base area of 12.76cm2a, what is the height of the cone?
把一个底面半径是2cm，高3cma圆柱形铁块铸成底面积12.七6cm2a圆锥，求圆锥高是多少？
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