Q. 123.7( 3 Votes )
The circumference of the base of a cylinder open at the top is 132 cm. The sum of radius and height is 41 cm. Find the cost of polishing the outer surface area of the cylinder at the rate of Rs. 10 per square decimeter.
Answer :
Concept Used: Circumference of the base of the cylinder = 2πr
Outer Surface Area of cylinder = 2πrh
Where r = radius of the cylinder and h = height of the cylinder.
Given: r + h = 41 cm
Circumference of the base of cylinder = 2πr = 132 cm
Explanation:
Let us calculate the value of “r” first,
2πr = 132 cm
r = (3 × 7) cm
r = 21 cm.
Now, let us calculate the height of the cylinder,
r + h = 41
Putting the obtained value of “r” we get,
21 + h = 41
h = 20 cm
Now putting the values of “r” and “h” in the formula of Outer Surface Area of the cylinder we get,
The outer surface area of cylinder = 2πr
The outer surface area of cylinder
The outer surface area of cylinder = 120 × 22
The outer surface area of cylinder = 2640 cm2
Hence, the outer surface area of a cylinder is 2640 cm3.
Rate this question :






















The lateral surface area of a cylinder is
RS Aggarwal & V Aggarwal - MathematicsThe diameter of a roller, 1 m long, is 84 cm. If it takes 500 complete revolutions to level a playground, the area of the playground is
RS Aggarwal & V Aggarwal - MathematicsThe ratio between the curved surface area and the total surface area of a right circular cylinder is 1 : 2. If the total surface area is 616 cm2, then the volume of the cylinder is
RS Aggarwal & V Aggarwal - MathematicsThe ratio of the curved surface area and the total surface area of a circular cylinder is 1:2 and the total surface area is 616 cm2. Find its volume.
RS Aggarwal & V Aggarwal - MathematicsThe total surface area of a cylinder is 462 cm2 and its curved surface area is one-third of its total surface area. Find the volume of the cylinder.
RS Aggarwal & V Aggarwal - MathematicsWhich is false in case of a hollow cylinder?
RS Aggarwal & V Aggarwal - MathematicsIf the curved surface area of a cylinder is 1760 cm2 and its base radius is 14 cm, then its height is
RS Aggarwal & V Aggarwal - MathematicsThe curved surface area of a cylindrical pillar is 264 m2 and its volume is 924 m3. The height of the pillar is
RS Aggarwal & V Aggarwal - Mathematics