Question

ss below @SmokeyBrown @Florisalreadytaken

Answer 1

It's more similarity ratios, and the numbers are nice and neat this time.
Notice the diagonals of the two triangles. The diagonal of MNO is length 6, which is 3 times as long as the diagonal of JKL, length 2.
Since the two triangles are similar, this tells us that MNO sides will be 3 times as long as the corresponding sides of JKL.
So, given that JK corresponds to MN and JK is length 1.4, we know that MN should be 3 * 1.4, yes?

Answer 2

4.2?

Answer 3

Yup, I think that's right!