If two solid hemispheres of same base radius are joined together along their bases, then curved surface area of this new solid is
A. 4πr²

B. 6πr²

C. 3πr²

D. 8πr²

From a solid cylinder of height 2.8 cm and diameter 4.2 cm, a conical cavity of the same height and same diameter is hollowed out. Find the total surface area of the remaining solid. .

A solid wooden toy is in the form of a hemisphere surmounted by a cone of same radius. The radius of hemisphere is 3.5 cm and the total wood used in the making of toy is . Find the height of the toy. Also, find the cost of painting the hemispherical part of the toy at the rate of ` 10 per cm².

In Fig. 16.57, from a cuboidal solid metallic block, of dimensions 15 cm × 10 cm × 5 cm, a cylindrical hole of diameter 7 cm is drilled out. Find the surface area of the remaining block.

A tent is in the form of a right circular cylinder surmounted by a cone. The diameter of cylinder is 24 m. The height of the cylindrical portion is 11 m while the vertex of the cone is 16 m above the ground. Find the area of canvas required for the tent.

If the total surface area of a solid hemisphere is 462 cm², find its volume.

A cylindrical bucket, 32 cm high and with radius of base 18 cm, is filled with sand. This bucket is emptied out on the ground and a conical heap of sand is formed. If the height of the conical heap is 24 cm, find the radius and slant height of the heap.

The surface area of a solid metallic sphere is 616 cm². It is melted and recast into a cone of height 28 cm. Find the diameter of the base of the cone so formed .

504 cones, each of diameter 3.5 cm and height of 3 cm, are melted and recast into a metallic sphere.

Find the diameter of the sphere and hence find its surface area. (Use π = 22/7)

Two cubes each of volume 27 cm³ are joined end to end to form a solid. Find the surface area of the resulting cuboid.

The volume of a hemisphere is 19404 cm³. The total surface area of the hemisphere is