Nihao! Zao an..
The answer is D. 4
Solution and explanation:
This is a combined variation.
[tex]y = \frac{k {x}^{2} }{z} [/tex]
[tex]3 = \frac{ { k3}^{2} }{12} [/tex]
[tex] \frac{3}{1} = \frac{k9}{12} [/tex]
(Do the Cross Multiplication) (3 x 12, 1 x k9)
[tex]36 = k9[/tex]
(Cancel)
[tex] \frac{36}{9} = \frac{k9}{9} [/tex]
[tex] \frac{36}{9} = k[/tex]
(Simplify) (36 divided by 9)
4 = k
k = 4.
Therefore, the constant of variation (k) is 4.
~ GongzhuSisi(◕ᴗ◕✿)
Hope it helps. ehehe(≧▽≦)
