NCERT Class 9 Maths Chapter 11 Surface Areas and Volumes Solutions
NCERT Class 9 Maths Chapter 11 Surface Areas and Volumes Solutions Exercise 11.1 Q.1. Diameter of the base of a cone is 10.5 cm and its slant height is 10 cm. Find its curved surface area. Ans: ∴ Diameter of the base = 10.5cm Slant height (l) = 10cm ∴ Curved surface area of the cone = πrl Q.2. Find the total surface area of a cone, if its slant height is 21 m and diameter of its base is 24 m. Ans: Slant height (l) = 21m Diameter of base = 24m ∴ Total curved surface area of the cone = πr(l + r) Q.3. Curved surface area of a cone is 308cm² and its slant height is 14 cm. Find (i) radius of the base and (ii) total surface area of the cone. Ans: (i) Slant height (l) = 14cm Curved surface area = 308cm² Hence the radius of the base is 7 cm. (ii) Total surface area of the cone = πr(l + r) Hence the total surface area of the cone is 462cm² Q. 4 A conical tent is 10 m high and the radius of its base is 24 m. Find (i) slant height of the tent. (ii) cost of...