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Triangle Arcs

\begin{figure}\begin{center}\BoxedEPSF{TriangleArcs.epsf}\end{center}\end{figure}

In the above figure, the curves are arcs of a Circle and

$\displaystyle a$ $\textstyle =$ $\displaystyle BC$ (1)
$\displaystyle b$ $\textstyle =$ $\displaystyle CA=CP$ (2)
$\displaystyle c$ $\textstyle =$ $\displaystyle BA=BQ.$ (3)

Then
\begin{displaymath}
PQ^2=2BP\cdot QC.
\end{displaymath} (4)

The figure also yields the algebraic identity
\begin{displaymath}
(b+c-\sqrt{b^2+c^2}\,)^2=2(\sqrt{b^2+c^2}-b)(\sqrt{b^2+c^2}-c).
\end{displaymath} (5)

See also Arc


References

Berndt, B. C. Ramanujan's Notebooks, Part IV. New York: Springer-Verlag, pp. 8-9, 1994.

Dharmarajan, T. and Srinivasan, P. K. An Introduction to Creativity of Ramanujan, Part III. Madras: Assoc. Math. Teachers, pp. 11-13, 1987.




© 1996-9 Eric W. Weisstein
1999-05-26