Using the data given below, find the unknown:
\(\triangle ABC\) is right-angled at \(A\), and \(AD\) \(\perp\) \(CB\).
If \(AC\) \(=\) 6.2 \(cm\), \(AD\) \(=\) 3.2 \(cm\) and \(BD\) \(=\) 5.1 \(cm\), find the value of \(AB\).
\(AB\) \(=\) \(cm\)
[Note: Round off the answer obtained to one decimal places]