Direct and Inverse Proportion

\(a^2\) is directly proportional to \(b^2\), where \(a,b>0\). When \(a=6\), \(b=4\).

1. Find the equation connecting \(a^2\) and \(b^2\).

2. Hence express \(a\) in terms of \(b\).

3. Find \(a\) when \(b=10\).