Multiple choice

Find the area of the ring between two concentric circles, whose circumference are 132 cm and176 cm. दो संकेद्री वृत्तो जिनकी परिधि 132 सेमी और 176 सेमी है के बीच बने वलय का क्षेत्रफल ज्ञात कीजिये।

  1. 1080

  2. 1078

  3. 1060

  4. 1108

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

For the first circle: circumference = 2πr1 = 132, so r1 = 132/(2π) = 21 cm. For the second circle: circumference = 2πr2 = 176, so r2 = 176/(2π) = 28 cm. Area of ring = π(r2² - r1²) = π(28² - 21²) = π(784 - 441) = π × 343. Using π = 22/7: Area = (22/7) × 343 = 22 × 49 = 1078 sq cm.