Okay, here we have this:
Considering the provided information, and figures, we are going to find the requested length, so we obtain the following:
Let us remember that if two figures are proportional, then they are proportional between corresponding segments, therefore we have:
[tex]\begin{gathered} \frac{RS}{VW}=\frac{PS}{TW} \\ \frac{35}{25}=\frac{PS}{15} \\ PS=\frac{35}{25}\cdot15 \\ PS=\frac{7}{5}\cdot15 \\ PS=\frac{105}{5} \\ PS=21 \end{gathered}[/tex]
Finally we obtain that the measure of PS is 21 units.
