To convert an angle measured in radians into seconds of arc, the...

We know the relationship between radians and degrees is $\pi \text{ rad} = 180^\circ$.

Therefore, $1 \text{ rad} = \dfrac{180}{\pi} \text{ degrees}$.

Since $1^\circ = 60'$ (minutes of arc)$and 1' = 60''$ (seconds of arc), we have $1^\circ = 3600''$.

Substituting this into the radian conversion gives $1 \text{ rad} = \dfrac{180}{\pi} \times 3600''$.

Thus, to convert an angle from radians to seconds of arc, the value must be multiplied by the factor $\dfrac{180 \times 3600}{\pi}$.

Answer: $\dfrac{180 \times 3600}{\pi}$