Find the Variation Equation for the Variation Statement $y$ Varies Directly as the Square Of

Multiple Choice

Find the variation equation for the variation statement.
- $y$ varies directly as the square of $x ; y = - \frac { 81 } { 5 }$ when $x = 9$

A) $y = \left( - \frac { 1 } { 5 } x \right) ^ { 2 }$
B) $y = - \frac { 81 } { 5 } x$
C) $y = - \frac { 1 } { 5 } x ^ { 2 }$
D) $y = \left( - \frac { 81 } { 5 } x \right) ^ { 2 }$