Advertisements
Advertisements
प्रश्न
Find the total surface area of a hemisphere of radius 10 cm. [Use π = 3.14]
Advertisements
उत्तर

Radius (r) of hemisphere = 10 cm
Total surface area of hemisphere = Curved surface area of a hemisphere + Area of circular end of hemisphere
= 2πr2 + πr2
= 3πr2
= [3 × 3.14 × (10)2] cm2
= 942 cm2
Therefore, the total surface area of such a hemisphere is 942 cm2.
APPEARS IN
संबंधित प्रश्न
The surface area of a solid metallic sphere is 2464 cm2. It is melted and recast into solid right circular cones of radius 3.5 cm and height 7 cm. Calculate:
- the radius of the sphere.
- the number of cones recast. (Take π = `22/7`)
The surface area of a solid sphere is increased by 12% without changing its shape. Find the percentage increase in its:
- radius
- volume
What is the least number of solid metallic spheres, each of 6 cm diameter, that should be melted and recast to form a solid metal cone whose height is 45 cm and diameter 12 cm?
Find the radius of a sphere whose surface area is 154 cm2.
The ratio of the total surface area of a sphere and a hemisphere of same radius is
A sphere and a cube are of the same height. The ratio of their volumes is
If a solid sphere of radius r is melted and cast into the shape of a solid cone of height r, then the radius of the base of the cone is
A cone and a hemisphere have equal bases and equal volumes the ratio of their heights is
The model of a building is constructed with the scale factor 1 : 30.
(i) If the height of the model is 80 cm, find the actual height of the building in meters.
(ii) If the actual volume of a tank at the top of the building is 27m3, find the volume of the tank on the top of the model.
A sphere has the same curved surface area as the curved surface area of a cone of height 36 cm and base radius 15 cm . Find the radius of the sphere .
Find the volume of the hollow sphere whose inner diameter is 8 cm and the thickness of the material of which it is made is 1 cm .
The internal and external diameters of a hollow hemi-spherical vessel are 21 cm and 28 cm respectively. Find volume of material of the vessel.
From a rectangular solid of metal 42 cm by 30 cm by 20 cm, a conical cavity of diameter 14 cm and depth 24 cm is drilled out. Find: the volume of remaining solid
A certain number of metallic cones, each of radius 2 cm and height 3 cm are melted and recast into a solid sphere of radius 6 cm. Find the number of cones used.
Find the volume and surface area of a sphere of diameter 21 cm.
There is a ratio 1: 4 between the surface area of two spheres, find the ratio between their radius.
The radius of two spheres are in the ratio of 1 : 3. Find the ratio between their volume.
A spherical ball of radius 3 cm is melted and recast into three spherical balls. The radii of two of the balls are 1.5 cm and 2 cm. Find the diameter of the third ball.
The total surface area of a hemisphere is how many times the square of its radius
