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Question 25 - CBSE Class 10 Sample Paper for 2022 Boards - Maths Basic [MCQ] - Solutions of Sample Papers for Class 10 Boards

Last updated at Dec. 16, 2024 by Teachoo

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

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

Transcript

Question 25 If the circumference of a circle increases from 2𝜋 to 4 𝜋 then its area _____ the original area (a) Half (b) Double (c) Three times (d) Four times Now, Old Circumference = 2𝜋 2 × 𝜋 × Old Radius = 2𝜋 Old Radius = 𝟐𝜋/𝟐𝜋 Old Radius = 1 Now, (𝑵𝒆𝒘 𝑨𝒓𝒆𝒂)/(𝑶𝒍𝒅 𝑨𝒂𝒆𝒂)=(𝜋(𝑁𝑒𝑤 𝑅𝑎𝑑𝑖𝑢𝑠)^2)/(𝜋(𝑂𝑙𝑑 𝑅𝑎𝑑𝑖𝑢𝑠)^2 ) New Circumference = 4𝜋 2 × 𝜋 × New Radius = 4𝜋 New Radius = 𝟒𝜋/𝟐𝜋 NEw Radius = 2 =(𝝅 × 𝟐^𝟐)/(𝝅 × 𝟏^𝟐 ) =(𝜋 × 4)/(𝜋 × 1) = 4 Thus, New Area = 4 × 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 14 years. He provides courses for Maths, Science and Computer Science at Teachoo