Question 10: In Fig. 13.12, you see the frame of a lampshade. It is to be covered with a decorative cloth. The frame has a base diameter of 20 cm and height of 30 cm. A margin of 2.5 cm is to be given for folding it over the top and bottom of the frame. Find how much cloth is required for covering the lampshade.
Prerequisite
A closed cylinder has 3 surfaces:
- Curved or lateral surface
- Top
- Base
The formula to calculate the curved surface area and total surface area are quite simple to learn and derive.
Lateral or curved surface area of cylinder = 2πrh
r = radius, h = height (or length)
Total surface area of cylinder = 2πr ( r + h )
r = radius, h = height (or length)
It is recommended to understand the core concept of area, surface area and volume before we attempt any question based on these concepts.
Chapter 13 – Surface areas and Volumes
Concepts
- Area / Surface area / Volume – Introduction
- Surface Area of Cube and Cuboid
- Volume Of Cuboid and Cube
- Surface Area of Right Circular Cylinder
- Volume and capacity of Cylinder
- Right circular Cone
- Surface Area of Right circular Cone
- Volume of Cylinder vs Cone
- Litres and Cubic centimetre (cm³)
- Cubic meters to litres
