y varies directly with x²
[tex]\boxed {\boxed {y = kx^2}}[/tex]
When x = 12, y = 290
[tex]290 = k(12)^2[/tex]
[tex]144k = 290[/tex]
[tex]k = \dfrac{290}{144} [/tex]
[tex]k = \dfrac{145}{72} [/tex]
[tex]\boxed {\boxed {y = \dfrac{145x^2}{72} }}[/tex]
When y - 18
[tex]y = \dfrac{145(18)^2}{72}[/tex]
[tex]y = 652.5[/tex]
[tex]\boxed { \boxed { \text {Answer: y = 652.5}}}[/tex]
