Ex 11.1, 2 - Chapter 11 Class 9 Surface Areas and Volumes

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Ex 11.1, 2 Find the total surface area of a cone, if its slant height is 21 m and diameter of its base is 24 m. [𝐴𝑠𝑠𝑢𝑚𝑒 𝜋=22/7] Total surface area of cone = πr(r + l) Radius (r) of the base of cone = (24/2) m = 12 m Slant height (l) of cone = 21 m Total surface area of cone = πr(r + l) = [22/7×12×(12+21)] m2 = (22/7×12×33) m2 = 1244.57 m2