3 It is given that \(x\) is proportional to the product of the square of \(y\) and the positive square root of \(z\). When \(y = 2\) and \(z = 9 , x = 30\).
- Write an equation for \(x\) in terms of \(y\) and \(z\).
- Find the value of \(x\) when \(y = 3\) and \(z = 25\).