Answer:
4.8
Step-by-step explanation:
JK is twice as long as LM, so is 4.8 units long.
"Similar" means the sides of one figure have the same ratio as the corresponding sides of the other figure. We see that AB = 2×CD. JK corresponds to AB, and LM corresponds to CD.
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We could bother to calculate that sides of JKLM are 1.2 times as long as the corresponding sides of ABCD, but that is not necessary. We only need to find a convenient ratio between the side we want and some other known side. I like a ratio of 2, because it is easy to double a number. We find AB=2CD, so JK=2LM=2×2.4 = 4.8.
