Step-by-step explanation:
1) 6s^2
(s mean the length of each side, s=7)
= 6x7^2
= 294
2) 2(3)(2)+2(1)(2)+2(3)(1)
（l=length, w=wide, h=height)
= 12+4+6
= 22
3) 4(π)12^2
(r=radius)
= 576
