Page 1 - IX Math CBQ ch-11 Surface area
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SAI International School



                                                       Class :  IX

                                                                      Mathematics


                                         Competency Based Questions


        Ch-11 Surface Area and Volume





        1        If the radius of a cylinder is 4cm and height is 10cm, then the total surface area of
                a cylinder is:


                a. 440 sq.cm          b. 352 sq.cm.         c. 400 sq.cm             d. 412 sq.cm

        2        The diameter of the base of a cone is 10.5 cm, and its slant height is 10 cm. The

                curved surface area is:


                a. 150 sq.cm          b. 165 sq.cm             c. 177 sq.cm            d. 180 sq.cm

        3       A cone is 8.4 cm high and the radius of its base is 2.1 cm. It is melted and recast

                into a sphere. The radius of the sphere is

                (a) 4.2 cm            (b) 2.1 cm                  (c) 2. 4 cm                (d) 1.6 cm


        4       The total surface area of a cone whose radius is r/2 and slant height 2l is


                (a) 2πr(l+r)              (b) πr(l+(r/4))             (c) πr(l+r)                  (d) 2πrl

        5       A spherical ball is divided into two equal halves. Given that the curved surface area of

                each half is 56.57 cm, what will be the volume of the spherical ball?

        6       The paint in a certain container is sufficient to paint an area equal to 9.375 sq.m. How
                many bricks of dimensions 22.5 cm × 10 cm × 7.5 cm can be painted out of this
                container?
        7       The height of a cone is 16 cm and its base radius is 12 cm. Find the curved surface area
                and the total surface area of the cone. (Take π = 3.14)
        8       The slant height and base diameter of a conical tomb are 25 m and 14 m respectively.
                Find the cost of white-washing its curved surface at the rate of Rs.210 per 100 sq.m.
        9        A river 3 m deep and 40 m wide is flowing at the rate of 2 km per hour. How much water
                will fall into the sea in a minute?
        10       Meera has a piece of canvas whose area is 551 m . She uses it to have a conical tent
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                made, with a base radius of 7 m. Assuming that all the stitching margins and the wastage

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