Answer: root 70
Explanation:
starting info:
KL = 2NM
KM = 20
NO = 7
Using the fact the ratio of similar sides must be equal:
KL/NO = KM/NM
Therefore sub in values…
KL/7 = 20/NM
As KL = 2NM
2NM/7 = 20/NM
Rearrange:
2(NM)^2 = 140
(NM)^2 = 70
NM = root(70)
(Obviously take positive as can’t have negative length)