Chapter 13 Class 9 Surface Areas and Volumes

Class 9
Important Questions for Exam - Class 9

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### Transcript

Ex 11.1, 3 Curved surface area of a cone is 308 cm2 and its slant height is 14 cm. Find radius of the base and [ =22/7] It is given that Curved Surface Area of cone =308 rl = 308 22/7 14= 308 22 2= 308 r = (308/(2 22)) cm r = 7 cm Therefore, the radius of the circular end of the cone is 7 cm. Ex 11.1, 3 Curved surface area of a cone is 308 cm2 and its slant height is 14 cm. Find (ii) total surface area of the cone. [ =22/7] We know that l = 14 cm, r = 7 cm Total surface area of cone = r(l + r) = 22/7 7 (14 + 7) = 22/7 7 21 = 22 1 21 = 462 cm2 Therefore, the total surface area of the cone is 462 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 13 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.