~Given:
The right triangle ABC,
Use the Pythagorean theorem to find the length of the third side
[tex]\begin{gathered} AC=\sqrt[]{20^2+21^2} \\ AC=\sqrt[]{841} \\ AC=29 \end{gathered}[/tex]
The triangle DEF IS,
Use Pythagorean theorem.
[tex]\begin{gathered} DF^2=DE^2+EF^2 \\ 58^2=40^2+EF^2 \\ EF^2=1764 \\ EF=42 \end{gathered}[/tex]
It is also observed that sides of the triangles DEF are multiple sides of triangle ABC,
[tex]\begin{gathered} DE=40=2\times AB \\ EF=42=2\times BC \\ DF=58=2\times AC \end{gathered}[/tex]
Therefore,
[tex]\Delta ABC\text{ \textasciitilde }\Delta DEF[/tex]
