Given:
[tex]\text{ABCD}\approx QRST[/tex]
We need to find the length m.
Since the given figures are similar.
Then, the corresponding sides are proportional.
Therefore,
[tex]\frac{AB}{QR}=\frac{BC}{RS}=\frac{CD}{ST}=\frac{DA}{TQ}[/tex]
Considering (2)=(4), we get
[tex]\begin{gathered} \frac{BC}{RS}=\frac{DA}{TQ} \\ \frac{12}{m}=\frac{12}{3} \\ 12\times3=m\times12 \\ 3=m \\ \therefore m=3 \end{gathered}[/tex]
Hence, the length m is 3.
