03
Nov
Question 7: The inner diameter of a circular well is 3.5 m. It is 10 m deep. Find
- its inner curved surface area,
- the cost of plastering this curved surface at the rate of Rs. 40 per m2.
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.
Derivation of formula – Surface area of cylinder
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
