Question

If y is directly proportional to x2 and y = 487 when x = 18, find y if x = 6. (Round off your answer to the nearest hundredth.)AAAF

Answer 1

If y is directly proportional to x2 and y = 487 when x = 18, find y if x = 6.

`\begin{gathered} y\infty x^2 \\ y=kx^2 \\ k=(y)/(x^2ControlControl) \end{gathered}`

when y = 487 and x² = 18

`\begin{gathered} 487=k(18)^2 \\ k=(487)/(18^2) \\ k=(487)/(324) \\ k=1.507 \end{gathered}`

Find y when x = 6

`\begin{gathered} y=kx^2 \\ y=1.507x^2 \\ y=1.507(6)^2 \\ y=1.507(36) \\ y=54.11\text{ \lparen nearest hundredth\rparen} \end{gathered}`

Therefore the correct answer is 54.11