Differentiation - Connected Rates of Change

A cylinder with a base radius \(r\) cm, which varies, and a fixed height \(h\) cm is such that, its volume \(V\) is increasing at a rate twice the rate of its total surface area \(A\), with respect to time \(t\).

1. Express \(r\) in terms of \(h\).
2. Hence, or otherwise, show that \(h > 4\).