SOLUTION
Given the question in the question tab, the following are the solution steps to answer the question.
STEP 1: Write the given length of triangle ABC
[tex]\begin{gathered} AB=5,BC=5,AC=? \\ U\sin g\text{ pythagoras theorem,} \\ AC^2=5^2+5^2 \\ AC^2=25+25=50 \\ AC=\sqrt[]{50}=\sqrt[]{2\times25}=\sqrt[]{2}\times\sqrt[]{25}=5\sqrt[]{2} \end{gathered}[/tex]STEP 2: We carry out the second part of the direction in the question.
[tex]\begin{gathered} AB=5,DE\text{ is the corresponding side with length of 2} \\ \frac{DE}{AB}=\frac{2}{5}=0.4 \\ ratio\text{ = 0}.4 \end{gathered}[/tex]STEP 3: Use the ratio to multiply the other sides
[tex]\begin{gathered} U\sin g\text{ the sides listed in Step , we multiply the other two sides of triangle ABC with the ratio.} \\ BC=5,EF=0.4\times5=2 \\ \\ AC=5\sqrt[]{2},DF=0.4\times5\sqrt[]{2}=2\sqrt[]{2} \end{gathered}[/tex]