(a) Evaluate and express your answer in standard form : \(\frac{4.56 \times 3.6}{0.12}\)

(b) Without using mathematical tables or calculator, evaluate \((73.8)^{2} - (26.2)^{2}\).

(c) Simplify \(\sqrt{1\frac{19}{81}}\), expressing your answer in the form \(\frac{a}{b}\) where a and b are positive integers.