Given:
ST || RU
To find:
The measure of QS.
Solution:
In triangle QRU and QST,
[Common angle]
[Corresponding angle]
[AA property of similarity]
The corresponding sides of similar triangles are proportional.
![(QR)/(QS)=(QU)/(QT)](https://img.qammunity.org/2022/formulas/mathematics/high-school/jmqe67ww2nnuzkpzguk03cdt72t2dviewc.png)
![(23)/(QS)=(25)/(25+50)](https://img.qammunity.org/2022/formulas/mathematics/high-school/duqmtfoumspl0m4ph57jrd1eyl1b197nu9.png)
![(23)/(QS)=(25)/(75)](https://img.qammunity.org/2022/formulas/mathematics/high-school/5eknorrttbei8vovc8s47dj61i0qh7asjk.png)
![(23)/(QS)=(1)/(3)](https://img.qammunity.org/2022/formulas/mathematics/high-school/5tc08yceano9l7vl3litpwe1tz2lz5ywed.png)
On cross multiplication, we get
![3(23)=1(QS)](https://img.qammunity.org/2022/formulas/mathematics/high-school/nqo6usdpmpt53j4nn491mliocm0bfyxwd3.png)
![69=QS](https://img.qammunity.org/2022/formulas/mathematics/high-school/g89meyd9w89s64w4ehobk93yisz283unfu.png)
Therefore, the measure of QS is 69.