Approximation/Examples/22 over 7

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Theorem

$\dfrac {22} 7$ is a convenient approximation to $\pi$:

$\dfrac {22} 7 = 3 \cdotp \dot 14285 \dot 7$


Proof

\(\ds \dfrac {22} 7\) \(=\) \(\ds 3 \cdotp \dot 14285 \dot 7\)
\(\ds \pi\) \(\approx\) \(\ds 3 \cdotp 14159265\)
\(\ds \leadsto \ \ \) \(\ds \dfrac {22} 7 - \pi\) \(\approx\) \(\ds 0 \cdotp 0012645\)
\(\ds \leadsto \ \ \) \(\ds \dfrac {\frac {22} 7 - \pi} \pi\) \(\approx\) \(\ds 0 \cdotp 0004025\)
\(\ds \) \(\approx\) \(\ds 0 \cdotp 04025 \%\)

$\blacksquare$


Sources