Answer:
SU=25
Explanation:
We can set up a ratio as STU and SQR are similar because of the SAS similarity theorem.
TQ:SQ
SQ=ST+TQ=10+6=16
6:16=3:8
Therefore the ratio of STU:SQR is 3:8
We can use this to find SU
UR:SR=3:8
15:SR=3:8
Cross multiply
3SR=120
SR=40
SU=SR-UR
SU=40-15
SU=25