[tex] \frac{k}{x} [/tex] = [tex] \frac{w}{v} [/tex] Multiply both sides by v
[tex] \frac{kv}{x} [/tex] = w Multiply both sides by x
kv = wx Divide both sides by w
[tex] \frac{kv}{w} [/tex] = x Switch the sides to make it easier to read
x = [tex] \frac{kv}{w} [/tex]