Example 11 - A rectangular piece of paper 11 cm x 4 cm is folded

Example 11 - Chapter 11 Class 8 Mensuration - Part 2
Example 11 - Chapter 11 Class 8 Mensuration - Part 3

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Transcript

Example 11 A rectangular piece of paper 11 cm × 4 cm is folded without overlapping to make a cylinder of height 4 cm. Find the volume of the cylinder. Also, Length of rectangle = 11 cm Breadth of rectangle = 4 cm Since rectangle is rolled along its width to make cylinder Height of cylinder = Width of rectangle = 4 cm Let r be the radius of the cylinder. Now, since rectangle is rolled to become cylinder ∴ Perimeter of bottom of the cylinder = Length of the rectangle Circumference of circle = 11 2πr = 11 2×22/7×𝑟 = 11 44/7×𝑟 = 11 𝑟 = 11 × 7/44 𝑟 = 7/4 Now, Volume of cylinder = 𝜋𝑟^2 ℎ = 22/7×(7/4)^2×4 = 22/7×7/4×7/4×4 = (22 × 7)/4 = 154/4 = 77/2 = 38.5 cm3

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Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 13 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.