audio systems class, writing assignment help

I am taking a required class at stony brook university and it has me so lost in this audio systems class.. I was able to research and learn most of the homework questions but theres this one i just don’t get and cant find:

4. The period of a sine wave traveling through air is 0.003s.

A) Determine the frequency in Hz

B) Determine the angular frequency is radians per second.

C) Determine the wavelength at 20degreesC

please help me with these answers and also help me understand 🙁 

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