Answer:
14
Explanation:
(I go to a french school, so excuse my terminology, which might not always be correct)
The angle we can see, in GHI, is equal to 121°. JKL has an identical angle, meaning JKL is an enlargement (probably the wrong term, I apologise) of GHI. This means we can use the length of it's sides to find KL.
GH and GI are both multiplied by two (GH = 4 becomes JK = 8, GI = 5 becomes JL = 10) meaning you must multiply HI by 2 to find KL.
2*7 = 14
KL = 14