Find the radian measures corresponding to the following degree measures:

(i) 25°

(ii) – 47°30′

(iii) 240°

(iv) 520°

(i) Given: 25°

We know that 1° = radians

∴ 25° = 25 × = radians

∴ 25° = radians

(ii) Given: – 47°30′

We know that 1° = 60’

⇒ 1’ = °

∴ -30’ = - ° = - 0.5°

∴ -47° 30’ = -47.5°

We know that 1° = radians

∴ -47.5° = -47.5 × = -26388 × π = -0.8290 radians

∴ -47.5° = -0.8290 radians

(iii) Given: 240°

We know that 1° = radians

∴ 240° = 240 × = radians

∴ 240° = radians

(iv) Given: 520°

We know that 1° = radians

∴ 520° = 520 × = = 9.075 radians

∴ 520° = 9.075 radians