Chapter 4 - Section 4.1 - Angles and Radian Measure - Exercise Set - Page 533: 86

$\frac{53\pi}{6}$ radians

Given, 4 minutes and 25 seconds Total seconds in one revolution = 60 sec As we know, 1 min = 60 sec So 4 min = 240 sec Total sec = 240 + 25 = 265 sec Therefore, $\frac{265}{60}$ x $2\pi$ = $\frac{53\pi}{6}$ radians