Telangana SCERT Solution Class IX (9) Math Chapter 10 Surface Areas and Volumes Exercise 10.4
(1.) The radius of a sphere is 3.5 cm. Find its surface area and volume.
(2.) The surface area of a sphere is 1018-2/7 sq.cm. What is its volume?
Solution:
(3.) The length of equator of the globe is 44 cm. Find its surface area.
Solution:
(4.) The diameter of a spherical ball is 21 cm. How much leather is required to prepare 5 such balls.
(5.) The ratio of radii of two spheres is 2 : 3. Find the ratio of their surface areas and volumes.
Solution:
(6.) Find the total surface area of a hemisphere of radius 10 cm. (use π = 3.14)
Solution:
Given,
Radius of hemisphere = 10a, π = 3.14
Total surface area of hemisphere = 3πr2
= 3 x 3.14 x 102
= 3 x 3.14 x 100
= 3 x 314
= 942 cm2
(7.) The diameter of a spherical balloon increases from 14 cm. to 28 cm. as air is being pumped into it. Find the ratio of surface areas of the balloons in the two cases.
Solution:
(8.) A hemispherical bowl is made of brass, 0.25 cm. thickness. The inner radius of the bowl is 5 cm. Find the ratio of outer surface area to inner surface area.
Solition:
(9.) The diameter of a lead ball is 2.1 cm. The density of the lead used is 11.34 g/c3 . What is the weight of the ball?
Solution:
(11.) How many litres of milk can a hemispherical bowl of diameter 10.5 cm. hold?
Solution:
(12.) A hemispherical bowl has diameter 9 cm. The liquid is poured into cylindrical bottles of diameter 3 cm. and height 3 cm. If a full bowl of liquid is filled in the bottles, find how many bottles are required.
Solution:
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