m
4. Find the volume of a sphere whose surface area is 154 cm
5. The surface area of sphere is (5768) cm . Find its volume.
6. How many lead shots, each 3 mm in diameter, can be made from a
cuboid with dimensions (12 cm x 11 cm x 9 cm)?
7. How many lead balls, each of radius 1 cm, can be made from a sphere
of radius 8 cm?
8.A solid sphere of radius 3 cm is melted and then cast into smaller
spherical balls, each of diameter 0.6 cm. Find the number of small balls
thus obtained.
9. A metallic sphere of radius 10.5 cm is melted and then recast into
smaller cones, each of radius 3.5 cm and height 3 cm. How many cones
are obtained?
Answers
Answered by
1
4. Surface area of a sphere=4πr
2
=154cm
2
⇒4×
7
22
r
2
=154cm
2
⇒r
2
=
4
154
×
22
7
⇒r
2
=
4
49
⇒r=
4
49
∴r=
2
7
=3.5cm
Volume of the sphere=
3
4
πr
3
=
3
4
×
7
22
×(3.5)
3
=
21
88
×42.875=179.67cm
3
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