10th Class Mathematics Surface Areas and Volumes Question Bank Surface Area and Volume (Mensuration)

  • question_answer A cap is in the shape of a right circular cone of base radius 14 cm and height 26.5 cm. The approximate area of the sheet required to make 7 such caps is

    A)  \[9240\text{ }c{{m}^{2}}\]     

    B)  \[9420\text{ }c{{m}^{2}}\]     

    C)  \[8000\text{ }c{{m}^{2}}\]                 

    D)  \[8906\text{ }c{{m}^{2}}\]

    Correct Answer: A

    Solution :

    (a): The surface area of the sheet required to make the cap would be equal to the lateral surface area of the cap, which is given by the formula \[\pi \times r\times 1\] Since the base radius is 14 cm and height is 26.5 cm, the value of ?l? can be calculated using \[{{r}^{2}}+{{h}^{2}}={{1}^{2}}\Rightarrow 1=29.97=30\] Thus, 7 caps would require \[7\times \pi \times 14\times 30\]\[=9240\,\,c{{m}^{2}}\]          

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