Q132
The volume of a cylinder is 4312 cm3. Its curved surface area is one-third of its total surface area. Its curved surface area (in cm2) is: ( Take = 227 )
The volume of a cylinder is 4312 cm3. Its curved surface area is one-third of its total surface area. Its curved surface area (in cm2) is:
A.
528
B.
572
C.
616
AnswerD.
660
Answer: Option C
Solution
Answer: Option C
Solution:
Curved surface area = × total surface area2πrh = × [2πrh + 2πr2]
6πrh = 2πrh + 2πr2
4πrh = 2πr2
4h = 2r
h : r = 1x : 2x
Volume of cylinder = πr2h = 4312
× (2x)2 × x = 4312
× 4x3 = 4312
x3 = 49 × 7
x = 7
Curved surface area = 2πrh
= 2 × × (2 × 7) × 7
= 22 × 28
= 616 cm2