Question

The variables x and y vary directly. Use the values to find the constant of proportionality,

. Then write an equation that relates.
. Write any fractions in simplest form.
y=45; x=40

k=?

y=?

Direct Variation equation: y=kx

Answer 1

k = 9/8

y = 9/8x

Explanation:

I'm not as good as Mr. Verified here haha, but we did this in math class and I could use the points. Anyways, hope this helped! :)

Answer 2

`\bf \qquad \qquad \textit{direct proportional variation} \\\\ \textit{\underline{y} varies directly with \underline{x}}\qquad \qquad y=kx\impliedby \begin{array}{llll} k=constant\ of\\ \qquad variation \end{array} \\\\[-0.35em] \rule{34em}{0.25pt}\\\\ \textit{we know that } \begin{cases} y=45\\ x=40 \end{cases}\implies 45=k40\implies \cfrac{45}{40}=k\implies \cfrac{9}{8}=k \\\\\\ therefore\qquad \qquad \boxed{y=\cfrac{9}{8}x}`