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Transcript

Ex 9.2, 5 From a circular sheet of radius 4 cm, a circle of radius 3 cm is removed. Find the area of the remaining sheet. (Take π = 3.14) Our figure will look like Now, Area remaining = Area of bigger circle − Area of smaller circle Let’s find both these areas. Area of bigger circle Radius = r = 4 cm Area = 𝜋r2 = 3.14 × (4)2 = 3.14 × 16 = 𝟑𝟏𝟒/𝟏𝟎𝟎 × 16 = 5024/100 = 50.24 cm2 Area of smaller circle Radius = r = 3 cm Area = 𝜋r2 = 3.14 × (3)2 = 3.14 × 9 = 𝟑𝟏𝟒/𝟏𝟎𝟎 × 9 = 2826/100 = 28.26 cm2 Now, Area remaining = Area of bigger circle − Area of smaller circle Area remaining = 50.24 − 28.26 = 5024/100 − 2826/100 = (𝟓𝟎𝟐𝟒 − 𝟐𝟖𝟐𝟔)/𝟏𝟎𝟎 = 2198/100 = 21.98 cm2 Therefore, Area of remaining sheet is 21.98 cm2

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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, Social Science, Physics, Chemistry, Computer Science at Teachoo.