\begin{methode}
Pour les conversions degrés $\longleftrightarrow$ radians, on peut utiliser la relation:
\[
\frac{\pi}{180} \times \text{angle en degrés} = \text{angle en radians}.
\]
\end{methode}

\begin{questions}
\item $15^\circ$.
\[
\frac{\pi}{180} \times 15 = \frac{\pi}{12} \text{ rad}.
\]
\item $72^\circ$.
\[
\frac{\pi}{180} \times 72 = \frac{2\pi}{5} \text{ rad}.
\]
\item $135^\circ$.
\[
\frac{\pi}{180} \times 135 = \frac{3\pi}{4} \text{ rad}.
\]
\item $720^\circ$.
\[
\frac{\pi}{180} \times 720 = 4\pi         \text{ rad}.
\]
\end{questions}
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