9514 1404 393
Answer:
k = 2
Explanation:
All of the triangles are similar, so the ratio of short side to long side is the same for all.
4/8 = k/4
k = 16/8 = 2 . . . . multiply by 4 and simplify
The value of k is 2.
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Additional comment
By similar reasoning or by the Pythagorean theorem, ...
l = √20 = 2√5
m = √80 = 4√5