If the area of a sector of a circle is 462 cm2 and the central angle is 120°, then its radius is ____.
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 21 cm.
The area of a sector of a circle = (θ/360) × πr2
⇒ (120/360) × πr2 = 462
⇒ (1/3) × (22/7) × r2 = 462
⇒ r2 = 462 × 3 × (7/22) = 441
⇒ r = √(441) = 21