# Thread: Value of the constant

1. ## Value of the constant

Express the following statement as a formula with the value of the constant of proportionality determined with the given conditions: w variers directly as x and inversely as the square of y. If x=15 and y=5, then w=36. Ok my anwser is w=36 x/y^2 is this right I don't think so. Thanks for any help given.

2. Hello, kwtolley!

Express the following statement as a formula with the value of the constant of proportionality
determined with the given conditions:

$\displaystyle w$ variers directly as $\displaystyle x$ and inversely as the square of $\displaystyle y$.
If $\displaystyle x=15$ and $\displaystyle y=5$, then $\displaystyle w=36$.

Ok, my answer is: $\displaystyle w = \frac{36x}{y^2}$ . . . Is this right? . . . sorry, no
It looks like you started correctly: .$\displaystyle w \:= \:\frac{kx}{y^2}$

We're told that: .$\displaystyle x = 15,\;y=5,\;w = 36$

Plug them in: .$\displaystyle 36 = \frac{k\cdot15}{5^2}\quad\Rightarrow\quad k = 60$

Therefore: .$\displaystyle w \:=\:\frac{60x}{y^2}$

3. ## thank you note

thanks for checking my answer