I am a bit stuck on this question. I should be able to find the answers for a to f, but im wondering how I would get my values via the equation? Thank you in advance.

 

I am a bit stuck on this question. I should be able to find the answers for a to f, but im wondering how I would get my values via the equation? Thank you in advance.

View attachment 232637

That looks right, however if you approximate the frequency a little better you get a slightly lower time period.