The exercise is simple. You can find out the surface and the volume only applying the formulas
Atot = Alateral + 2·Abase = 2(12 + 12√3)·6√6 + 2· 144√3 = 144√6 + 432√2 + 288√3
V = Abase·h = 144√3 ·6√6 = 2592√2 cm3
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