Answer
$1.27\text{ radians}$
Work Step by Step
Recall that $2\pi\text{ radians}=360^\circ$.
Hence, $1^\circ= \frac{2\pi\text{ radians}}{360^\circ}=\frac{\pi\text{ radians}}{180^\circ}$.
Therefore:
$73^{\circ}=73\cdot1^{\circ}=73^\circ \cdot \frac{\pi\text{ radians}}{180^\circ} \approx1.27\text{ radians}$
