Check sibling questions

If the circumference of a circle increases from 2Ο€ to 4 Ο€ then its area _____ the original area

(a) Half Β  (b) Double Β (c) Three times Β  (d) Four times

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Question 25 If the circumference of a circle increases from 2πœ‹ to 4 πœ‹ then its area _____ the original area (a) Half (b) Double (c) Three times (d) Four times Now, Old Circumference = 2πœ‹ 2 Γ— πœ‹ Γ— Old Radius = 2πœ‹ Old Radius = πŸπœ‹/πŸπœ‹ Old Radius = 1 Now, (π‘΅π’†π’˜ 𝑨𝒓𝒆𝒂)/(𝑢𝒍𝒅 𝑨𝒂𝒆𝒂)=(πœ‹(𝑁𝑒𝑀 π‘…π‘Žπ‘‘π‘–π‘’π‘ )^2)/(πœ‹(𝑂𝑙𝑑 π‘…π‘Žπ‘‘π‘–π‘’π‘ )^2 ) New Circumference = 4πœ‹ 2 Γ— πœ‹ Γ— New Radius = 4πœ‹ New Radius = πŸ’πœ‹/πŸπœ‹ NEw Radius = 2 =(𝝅 Γ— 𝟐^𝟐)/(𝝅 Γ— 𝟏^𝟐 ) =(πœ‹ Γ— 4)/(πœ‹ Γ— 1) = 4 Thus, New Area = 4 Γ— Old Area So, the correct answer is (d)

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Davneet Singh

Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 12 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.