Find the power spectral density?
For the values of &omega;=100 to &omega;=300, |H(&omega;)| is a straight line and you have

x = &omega; = 100, y = |H(100)| = 16

x = &omega; = 300, y = |H(300)| = 24

So, solve the equation y = kx + c with the aforementioned values:

24 = k300 + c and 16 = k100 + c

And you get k = 4/100 and c = 12. So,

|H(150)| = (4/100) &times; 150 + 12 = 18

|H(200)| = (4/100) &times; 200 + 12 = 20