1) The direct variation formula is:
[tex]y=kx[/tex]2)If y=25 and x=4, then:
[tex]25=4\cdot k[/tex]3) The value of the constant of proportionality is:
[tex]\begin{gathered} 4k=25 \\ \Rightarrow k=\frac{25}{4} \end{gathered}[/tex]4)If x=3, then we have the following:
[tex]\begin{gathered} y=\frac{25}{4}x \\ x=3 \\ \Rightarrow y=\frac{25}{4}\cdot3=\frac{75}{4} \\ y=\frac{75}{4} \end{gathered}[/tex]therefore, if x=3, then y=75/4
