I really do not know what you are expected to do here.
Maybe
\(A={{1.15^2* \sqrt{5.4}} \over6.21}\\ lnA=ln1.15^2+ln5.4^{0.5}-ln6.21\\ lnA=2ln1.15+0.5ln5.4-ln6.21\\ lnA\approx -0.7034..\\ A\approx 0.49488\)
Why anyone would bother with that I have no idea.
The exact answer, without logs, is \(\frac{23\sqrt{15}}{180}\)
LaTex
A={{1.15^2* \sqrt{5.4}} \over6.21}\\
lnA=ln1.15^2+ln5.4^{0.5}-ln6.21\\
lnA=2ln1.15+0.5ln5.4-ln6.21\\
lnA\approx -0.7034..\\
A\approx 0.49488