Question

If y varies directly as x2 and y=290 when x=12, find y if x=18

Answer 1

y varies directly with x²


`\boxed {\boxed {y = kx^2}}`

When x = 12, y = 290


`290 = k(12)^2`


`144k = 290`


`k = (290)/(144)`


`k = (145)/(72)`


`\boxed {\boxed {y = (145x^2)/(72) }}`

When y - 18


`y = (145(18)^2)/(72)`


`y = 652.5`


`\boxed { \boxed { \text {Answer: y = 652.5}}}`