maths~~~~~~

正四面體的底面積是 (1/2)(6)(6)(sin60°) = 9√3 cm^2
設正四面體的高 = h , 底面正△ABC中心為O , 則ㄥOAB = 30°
(AB/2) / OA = cos30°
(6/2) / OA = √3/2
OA = 2√3
於是 h^2 + OA^2 = 6^2
h^2 + (2√3)^2 = 6^2
h^2 = 24
h = 2√6
該四面體的體積為 (1/3)(9√3)(2√6) = 18√2 cm^3

答：6個正四面體能組成一個正方體，即正方體的體積為：6 ^ 3 = 216 cm^3，

　　那麼正四面體的體積為：216 / 6 = 36 cm^3