Using two pieces of string stretched to the same tension, pythagoras discovered the ratio for creating the interval of a perfect octave was

The answer to this question would be 1:2

When you making sound with a string, the frequency is reversed with the string length. If you use a string with 2x length the frequency will become half of the first string. For a perfect octave, it will need 1:2 ratio of frequency or 1:4 tension

Answer: fn = wcos50 = 38.89(9.81)(cos50) = 245.23 n