[!URGENT!] In the figure PQ is parallel to RS. The length of QT is 4 cm; the length of TS is 6 cm; the length of PQ is 10 cm. What is the length of RS?

Answer:
Short answer: D) 15
Step-by-step explanation:
Parallel lines in this kind of triangle are always in a strict ratio of small to large or large to small based on how you look at it.
So we have 4cm to 6cm, which is 2:3 ratio. We know the smaller side, but want the larger side, so we can set up 2/3 = 10/?
the ? is 15.