Write an Equation to Describe the Variation $\mathrm { q }$

Write an equation to describe the variation. Use k for the constant of proportionality.
- $\mathrm { q }$ varies directly as the square of $\mathrm { r }$ and inversely as $\mathrm { s }$ .

A) $\mathrm { q } = \frac { \mathrm { kr } ^ { 2 } } { \mathrm {~s} }$
B) $\mathrm { q } = \mathrm { k } + \mathrm { r } ^ { 2 } - \mathrm { s } ^ { 2 }$
C) $q = k ^ { 2 } s$
D) $\mathrm { q } = \frac { \mathrm { ks } } { \mathrm { r } ^ { 2 } }$