Answer:
PM = 26.1
Step-by-step explanation:
If they are both similar shapes, each side must be scaled up to the same factor. To find the missing side length, you must know that the side lengths are multiplied by the exact same number. Knowing this, you can set the ratio of the side lengths equal to each other and then cross-multiply to find the missing side length.
<----- Ratio
<----- Insert side lengths
15x = 392 <----- Cross multiply
x = 26.1 <----- Divide both sides by 15