Question

The ration between the curved surface area and the total surface area of a right circular cylinder is 1:2. Find the volume of the cylinder, if its total surface area is 616 cm2.

Answer 1

Answer:

Given that:Curved surface area : Total surface area =1:2

Curved surface area :616=1:2

Curved surface area=

2

616

=308

⇒

2πr(h+r)

2πrh

=

2

1

⇒

h+r

h

=

2

1

⇒2h=h+r

⇒h=r

Curved Surface area=2πrh=2πr

2

=308 since h=r

⇒2×

7

22

r

2

=308

⇒r

2

=

44

308×7

=49

⇒r=7cm

Since r=h

h=7cm

Volume of the cylinder=πr

2

h=

7

22

×7×7×7=1078cm

3

∴ Volume of the cylinder is 1078 cu cm.