Advertisements
Advertisements
Question
The ratio between the curved surface area and the total surface area of a right circular cylinder is 1 : 2. Find the ratio between the height and radius of the cylinder.
Solution
Curved surface area of a cylinder = 2πrh
Total surface area of a cylinder = 2πr(r + h)
The ratio between the curved surface area and the total surface area of a cylinder is 1 : 2.
∴ `1/2 = (2pirh)/(2pir(r + h))`
⇒ `1/2 = h/((r + h))`
⇒ 2h = (r + h)
⇒ 2h – h = r
⇒ h = r
∴ Ratio of height and radius = 1 : 1.
APPEARS IN
RELATED QUESTIONS
The height of a right circular cylinder is 10.5 cm. If three times the sum of the areas of its two circular faces is twice the area of the curved surface area. Find the radius of its base.
A well is dug 20 m deep and it has a diameter of 7 m. The earth which is so dug out is spread out on a rectangular plot 22 m long and 14 m broad. What is the height of the platform so formed?
How many litres of water flow out of a pipe having an area of cross-section of 5 cm2 in one minute, if the speed of water in the pipe is 30 cm/sec?
The height of sand in a cylindrical shaped can drops 3 inches when 1 cubic foot of sand is poured out. What is the diameter, in inches, of the cylinder?
Find the area of base and radius of a cylinder if its curved surface area is 660 sqcm and height is 21 cm.
The radius of a solid cylinder decreases by 10% and its height increases by 20%. Find the change in percentage of its volume and curved surface area
In a cylinder, radius is doubled and height is halved, curved surface area will be ______.
30 circular plates, each of radius 14 cm and thickness 3 cm are placed one above the another to form a cylindrical solid. Find the total surface area.
In the above question, curved surface area of A is ______ curved surface area of B.
A rectangular sheet of paper of size 11 cm × 7 cm is first rotated about the side 11 cm and then about the side 7 cm to form a cylinder, as shown in the diagram. The ratio of their curved surface areas is ______.
