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Ex 13.7, 2 - Chapter 13 Class 9 Surface Areas and Volumes - Part 3

Ex 13.7, 2 - Chapter 13 Class 9 Surface Areas and Volumes - Part 4

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Ex 11.3, 2 Assume π = 22/7 , unless stated otherwise. Find the capacity in litres of a conical vessel with (ii) height 12 cm, slant height 13 cm Given height of cone = h = 12 cm Slant height = l = 13 cm Let radius of cone = r cm We know that l2 = h2 + r2 132 = 122 + r2 132 – 122 = r2 r2 = 132 – 122 r2 = 169 – 144 r2 = 25 r = √("25" ) r = √(5^2 ) = 5 cm Capacity = Volume of cone = 1/3πr2h = 1/3 × 22/7 × 5 × 5 × 12 cm3 = 1× 22/7 × 5 × 5 × 4 cm3 = 2200/7 cm3. = 2200/7 × 1/1000 litres = 11/35 litres

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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.