Page 3 - Lesson Notes-2-Ch.13 SA and Volumes(Cylinder)

Therefore,

.
Therefore, C1: C2 = 5: 6

Example-4

2
Find the total surface area (in cm ) of a cylinder of radius 3.5 cm and height 10
cm.
Solution.
Here, Radius of the base = 3.5 cm
Height=10 cm

Total surface area of a cylinder = 2 r(r + h)
22
= 2 × × 3.5(3.5 + 10)
7
22
2
= [2 × × 3.5 × 13.5] cm
7
2
= 297 cm
2
Therefore, the area of the metal sheet required to make the vessel = 297 cm .
Example-5
Find the volume of a cylinder of diameter 14 cm and height 20 cm.

Solution.
Here, Diameter (d) = 14 cm Height (h)= 20 cm

14
Radius ( r) = = = 7 cm
2 2

Volume = ℎ = 22 × 7 × 7 × 20 = 3080
2
3
7

Example-6
At a Ramzan Mela, a stall keeper in one of the food stalls has a large cylindrical
vessel of base radius 15 cm filled up to a height of 32 cm with orange juice. The
juice is filled in small cylindrical glasses of radius 3 cm up to a height of 8 cm and
sold for Rs 3 each. How much money does the stall keeper receive by selling the
juice completely?
Solution.
Here,
Cylindrical Vessel
Radius of the base ( R )= 15 cm
Height(H) = 32 cm
Volume of juice in the vessel= R H
2

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