Calculation:

In \(\displaystyle\triangle{A}{B}{C}{\quad\text{and}\quad}\triangle{D}{E}{F}\)

\(\displaystyle\frac{{{A}{B}}}{{{D}{F}}}=\frac{{{4.2}}}{{{2.8}}}\)

\(\displaystyle\frac{{{A}{B}}}{{{D}{F}}}=\frac{{3}}{{2}}\)

\(\displaystyle\frac{{{B}{C}}}{{{E}{F}}}=\frac{{{4.8}}}{{{3.2}}}\)

\(\displaystyle\frac{{{B}{C}}}{{{E}{F}}}=\frac{{3}}{{2}}\)

\(\displaystyle\frac{{{A}{C}}}{{{D}{E}}}=\frac{{{3.6}}}{{{2.4}}}\)

\(\displaystyle\frac{{{A}{C}}}{{{D}{E}}}=\frac{{3}}{{2}}\)

Hence, \(\displaystyle\triangle{A}{B}{C}{\quad\text{and}\quad}\triangle{D}{E}{F}\) are similar.

In \(\displaystyle\triangle{A}{B}{C}{\quad\text{and}\quad}\triangle{D}{E}{F}\)

\(\displaystyle\frac{{{A}{B}}}{{{D}{F}}}=\frac{{{4.2}}}{{{2.8}}}\)

\(\displaystyle\frac{{{A}{B}}}{{{D}{F}}}=\frac{{3}}{{2}}\)

\(\displaystyle\frac{{{B}{C}}}{{{E}{F}}}=\frac{{{4.8}}}{{{3.2}}}\)

\(\displaystyle\frac{{{B}{C}}}{{{E}{F}}}=\frac{{3}}{{2}}\)

\(\displaystyle\frac{{{A}{C}}}{{{D}{E}}}=\frac{{{3.6}}}{{{2.4}}}\)

\(\displaystyle\frac{{{A}{C}}}{{{D}{E}}}=\frac{{3}}{{2}}\)

Hence, \(\displaystyle\triangle{A}{B}{C}{\quad\text{and}\quad}\triangle{D}{E}{F}\) are similar.