Answer:
10x.
Step-by-step explanation:
It is given that,
JK = 3x
LM = 12x
JM = 25x
Let as consider the line as shown in the below figure.
From the figure it is clear that,
[tex]JK+KL+LM=JM[/tex]
[tex]3x+KL+12x=25x[/tex]
[tex]KL+15x=25x[/tex]
[tex]KL=25x-15x[/tex]
[tex]KL=10x[/tex]
Therefore, the length of KL is 10x.