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If to use value of = 3.14159, you will get L = 51.88 ft (rounded to 2 dp).
If to use value of = , you will get L = 51.83 ft (rounded to 2 dp).
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If you keep coming up with 51.88, as you write in your post, it means (at least I understand it this way from your post)
that you did not make the calculations on your own, but got them from the third party.
Am I right ?