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9.[tex]V = \frac{\sqrt{3}}{2}a^{2}h[/tex]
[tex]V = \frac{\sqrt{3}}{2}(4)^{2}(8)[/tex]
[tex]V = \frac{\sqrt{3}}{2}(16)(8)[/tex]
[tex]V = \frac{\sqrt{3}}{2}(128)[/tex]
[tex]V = \frac{128\sqrt{3}}{2}[/tex]
[tex]V = 64\sqrt{3}\ cm^{3}[/tex]
The answer is D.

10. V = ¹/₃πr²h
V = ¹/₃(3.14)(6)²(10)
V = ¹/₃(3.14)(36)(10)
V = ¹/₃(3.14)(360)
V = ¹/₃(1130.4)
V = 376.8 cm³
The answer is C.

11. V = ¹/₃πr²h
V = ¹/₃(3.14)(6)²(10)
V = ¹/₃(3.14)(36)(10)
V = ¹/₃(3.14)(360)
V = ¹/₃(1130.4)
V = 376.8 cm³
The answer is C.

12. V = 1¹/₃πr³
V = 1¹/₃(3.14)(3)³
V = 1¹/₃(3.14)(27)
V = 1¹/₃(84.78)
V = 113.04 cm³
The answer is C.

13. V = 1¹/₃πr³
V = 1¹/₃(3.14)(12)³
V = 1¹/₃(3.14)(1728)
V = 1¹/₃(5425.92)
V = 7234.56 cm³
The answer is A.

14. S = 4πr²
  324π = 4(3.14)(r)²
324(3.14) = 4(3.14r²)
1017.36 = 12.56r²
12.56 12.56
  81 = r²
  9 = r

V = 1¹/₃πr³
V = 1¹/₃(3.14)(9)³
V = 1¹/₃(3.14)(729)
V = 1¹/₃(2289.06)
V = 3052.08
The answer is D.

15. The answer is A.
16. The answer is A.
17. The answer is B.
18. The answer is C.