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Home » A fez, the cap used by the Turks, is shaped like the frustum of a cone (see Fig.). If its radius on the open side is 10 cm, radius at the upper base is 4 cm and its slant height is 15 cm, find the area of material used for making it.
A fez, the cap used by the Turks, is shaped like the frustum of a cone (see Fig.). If its radius on the open side is 10 cm, radius at the upper base is 4 cm and its slant height is 15 cm, find the area of material used for making it.
CBSE | Class 10 | Exercise 13.4 | Maths | NCERT | Surface Areas And Volumes
A fez, the cap used by the Turks, is shaped like the frustum of a cone (see Fig.). If its radius on the open side is 10 cm, radius at the upper base is 4 cm and its slant height is 15 cm, find the area of material used for making it.
Ncert solutions class 10 chapter 13-23

  Given,

For the lower roundabout end, span (r_1) = 10 cm

For the upper roundabout end, span (r_2) = 4 cm

Inclination tallness (l) of frustum = 15 cm

Presently,

The space of material to be utilized for making the fez = CSA of frustum + Area of upper roundabout end

    \[CSA\text{ }of\text{ }frustum\text{ }=\text{ }\pi \left( r_1+r_2 \right)\times l\]

    \[=\text{ }210\pi \]

Also, Area of upper round end

    \[=\text{ }\pi r_2^2\]

    \[=\text{ }16\pi \]

    \[\therefore The\text{ }space\text{ }of\text{ }material\text{ }utilized\text{ }=\text{ }710\text{ }\times \text{ }\left( 2/7 \right)\text{ }cm^2\]

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