Q126
A solid cylinder has total surface area of 462 sq. cm. Its curved surface area is one third of the total surface area. Then the radius of the cylinder is
A.
7 cm
AnswerB.
3.5 cm
C.
9 cm
D.
11 cm
Answer: Option A
Solution
Answer: Option A
Solution:
According to the questionCurved surface area = × Total surface area
2πrh = × 2πr(h + r)
h = 2r . . . . . . (1)
Now total surface area = 2πr(h + r) = 462
By using equation - (1)
2πr(2r + r) = 462
r = 7 cm