Home
Class 10
MATHS
The height and base radius of a metallic...

The height and base radius of a metallic cone are 216 cm and 16 cm respectively.It melted and recast into a sphere .Find the surface area of the spere.

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem step by step, we will find the surface area of the sphere formed by melting a cone with given dimensions. ### Step 1: Find the Volume of the Cone The volume \( V \) of a cone is given by the formula: \[ V = \frac{1}{3} \pi r^2 h \] where \( r \) is the base radius and \( h \) is the height of the cone. Given: - Base radius \( r = 16 \) cm - Height \( h = 216 \) cm Substituting the values into the volume formula: \[ V = \frac{1}{3} \pi (16)^2 (216) \] ### Step 2: Calculate \( (16)^2 \) Calculating the square of the radius: \[ (16)^2 = 256 \] ### Step 3: Substitute and Simplify the Volume Now substitute \( 256 \) into the volume formula: \[ V = \frac{1}{3} \pi (256)(216) \] ### Step 4: Calculate \( 256 \times 216 \) Calculating the product: \[ 256 \times 216 = 55296 \] ### Step 5: Substitute Back to Find Volume Now substitute back into the volume formula: \[ V = \frac{1}{3} \pi (55296) \] \[ V = 18432 \pi \text{ cm}^3 \] ### Step 6: Set Volume of Cone Equal to Volume of Sphere Since the cone is melted and recast into a sphere, the volume of the sphere \( V_s \) is equal to the volume of the cone: \[ V_s = \frac{4}{3} \pi R^3 \] Setting the volumes equal: \[ 18432 \pi = \frac{4}{3} \pi R^3 \] ### Step 7: Cancel \( \pi \) and Solve for \( R^3 \) Cancelling \( \pi \) from both sides: \[ 18432 = \frac{4}{3} R^3 \] ### Step 8: Multiply Both Sides by \( \frac{3}{4} \) To isolate \( R^3 \): \[ R^3 = 18432 \times \frac{3}{4} \] \[ R^3 = 13824 \] ### Step 9: Calculate \( R \) Now take the cube root of both sides to find \( R \): \[ R = \sqrt[3]{13824} = 24 \text{ cm} \] ### Step 10: Find the Surface Area of the Sphere The surface area \( A \) of a sphere is given by the formula: \[ A = 4 \pi R^2 \] Substituting \( R = 24 \) cm: \[ A = 4 \pi (24)^2 \] ### Step 11: Calculate \( (24)^2 \) Calculating the square of the radius: \[ (24)^2 = 576 \] ### Step 12: Substitute Back to Find Surface Area Now substitute back into the surface area formula: \[ A = 4 \pi (576) \] \[ A = 2304 \pi \text{ cm}^2 \] ### Final Answer The surface area of the sphere is: \[ \boxed{2304 \pi \text{ cm}^2} \]
Promotional Banner

Topper's Solved these Questions

  • VOLUME AND SURFACE AREA OF SOLIDS

    NAGEEN PRAKASHAN ENGLISH|Exercise Revisions Exercise Very Short Answer Questions|10 Videos
  • VOLUME AND SURFACE AREA OF SOLIDS

    NAGEEN PRAKASHAN ENGLISH|Exercise Revisions Exercise Short Answer Questions|10 Videos
  • VOLUME AND SURFACE AREA OF SOLIDS

    NAGEEN PRAKASHAN ENGLISH|Exercise Problems From NCERT/exemplar|10 Videos
  • TRIANGLES

    NAGEEN PRAKASHAN ENGLISH|Exercise Revision Exercise Long Questions|1 Videos

Similar Questions

Explore conceptually related problems

The base diameter and height of a metallic cone are 24cm and 6cm respectively .It is melted and recast in to a sphere.Find the surface area of the sphere.

The height and radius of base of a metallic cone are 27 cm and 16 cm respectively .It is melted and recast into a sphere .Find the radius and curved surface of the sphere.

Threee metallic cones of radius 2cm and height 9 cm are melted and recast in to a solid sphere. Find the radius of the sphere.

Threee metallic cones of radius 2cm and height 9cm are melted and recast in to a solid sphere. Fuind the radius of the sphere.

The radii of the internal and external surfaces of a metallic spherical shell are 3 cm and 5 cm respectively. It is melted and recast into a solid right circular cone of height 32 cm. Find the diameter of the base of the cone.

Metallic spheres of radii 6 cm, 8 cm and 10 cm respectively are melted and recasted into a single solid sphere. Taking pi = 3.1, find the surface area of the solid sphere formed.

The radii of the internal and external surfaces of a metallic spherical shell are 3 cm and 5 cm respectively. It is melted and recast into a solid right circular cylinder of height 10 2/3 cm. Find the diameter of the base of the cylinder.

The radius of the base and the height of a right circular cone are 7 cm and 24 cm respectively. Find the volume and the total surface area of the cone.

Metallic spheres of diameters 12 cm, 16 cm and 20 cm respectively, are melted to form a single solid sphere. Find the radius of the resulting sphere.

A cone of height 4 cm is melted and recast into a sphere of diameter 8 cm .Find the radius of the base of the cone.

NAGEEN PRAKASHAN ENGLISH-VOLUME AND SURFACE AREA OF SOLIDS-Exercise
  1. A cone of height 4 cm is melted and recast into a sphere of diameter 8...

    Text Solution

    |

  2. A metallic sphere of radius 7 cm is melted and recast in to right circ...

    Text Solution

    |

  3. The height and base radius of a metallic cone are 216 cm and 16 cm res...

    Text Solution

    |

  4. The base diameter and height of a metallic cone are 24cm and 6cm respe...

    Text Solution

    |

  5. (a) Three metallic spherical balls of radii 3 cm , 4cm and 5 cm are me...

    Text Solution

    |

  6. (a) How many balls of radius 1 cm can be drawn by melting metallic sph...

    Text Solution

    |

  7. (a) How many spherical balls of diameter 12 cm can be construct ed by ...

    Text Solution

    |

  8. A metallic sphere of radus 4 cm and a metallic cone of base readius 3 ...

    Text Solution

    |

  9. How many solid speherical balls of radus 3.5 cm can be recast by melt...

    Text Solution

    |

  10. There is some water in a cylindrical vessel of radus 6 cm a sphere of ...

    Text Solution

    |

  11. A solid metallic ball is dropped in a cylindrical vessel which has som...

    Text Solution

    |

  12. (i) The radius of a metallic sphere is 3 cm .It melted and recast in t...

    Text Solution

    |

  13. How many metallic cones of radius 3 cm and height 13.5 cm are required...

    Text Solution

    |

  14. The inner radius of a hemispherical cup is 9 cm and it is completely ...

    Text Solution

    |

  15. Two metallic cones of equal radii 2.1 cm and heights 4.1 cm and 4.3 cm...

    Text Solution

    |

  16. Threee metallic cones of radius 2cm and height 9cm are melted and reca...

    Text Solution

    |

  17. Threee metallic cones of radius 2cm and height 9 cm are melted and rec...

    Text Solution

    |

  18. A metallic cone is melted and recast in to a cylinder of same radius a...

    Text Solution

    |

  19. A cone of height 15 cm is melted and reacast in to cylinder of same ba...

    Text Solution

    |

  20. A cone of same height and same base radius is cut from a cylinder of h...

    Text Solution

    |