Mathematics
OpenStudy (anonymous):

y varies directly as the square of x. When x = 5, y = 5. Find y when x = 10.

OpenStudy (anonymous):

OpenStudy (zepp):

First, try to find 'k' $$\large y=kx^2$$

OpenStudy (anonymous):

did you get 20?

OpenStudy (anonymous):

yes? no?

OpenStudy (zepp):

Let's substitute x and y into our \large \begin{align} y&=kx^2\\ 5&=k*5^2 \\ 5 &= 25k\\ k& =5\div 25\\ k&=\frac{1}{5} \end{align}

OpenStudy (anonymous):

y = 10 y = 20 y = 50 y = 100 are my choices

OpenStudy (anonymous):

im pretty sure im right

OpenStudy (zepp):

Okay, now you found k, Find y when x = 10. $$\large y=\frac{1}{5}10^2$$ y=20 Yeah, you are right :)